Dermatopathology Flashcards
- This neoplasm derives from which structure?
A-Apocrine gland
B-Hair follicle
C-Eccrine duct
D-Subcutaneous fat E-Muscle
Correct choice: A. Apocrine gland
Explanation: Adenoid cystic carcinoma is considered a malignant apocrine tumor. It appears most commonly in the oral cavity and has a very unpredictable course.
- If positive, which immunohistochemical stain supports further evaluation with colonoscopy and cystoscopy?
A. CK20
B. Congo Red
C. S100
D. CD34
E. Neuron specific enolase
Correct choice: A. CK20
Explanation: Extramammary Paget’s Disease is an intraepithelial adenocarcinoma of apocrine glands that presents with a well-demarcated erythematous plaque in the genital area. Histologically, pagetoid cells stain positive for CK7, unlike pagetoid melanoma cells which stain positive for S100. CK20 staining has been associated with secondary EMP in the setting of underlying gastrointestinal or genitourinary carcinoma.
- A 60-year-old man presents with a poorly demarcated, symmetric, very painful patches of erythema and retiform purpura favoring the buttocks. Bullae and a dusky gray discoloration developed and ulcerations appeared with a black, leathery eschar. Upon palpation there is a surrounding subcutaneous induration that extends beyond the margins of the visibly active lesions. You perform a skin biopsy (see image). Which of the following is the most likely diagnosis?
A. Calciphylaxis
B. Cryoglobulinemia
C. Protein C deficiency
D. Warfarin necrosis
E. Subcutaneous fat necrosis
Correct choice: A. Calciphylaxis
Explanation: calciphylaxis is characterized by intimal fibrosis and medial vascular calcification (that can become transmural) as well as transdifferentiation of vascular smooth muscle cells into osteoblast-like cells; these changes plus thrombosis lead to ischemic necrosis of the skin and soft tissues. Early lesions usually present as poorly demarcated, often symmetric, very painful patches of erythema or retiform purpura. They favor areas with abundant adipose tissue or sites of trauma. Bullae or a dusky gray color may then develop, signifying imminent tissue necrosis and the appearance of ulcerations with black, leathery eschars. Often there is surrounding subcutaneous induration that extends beyond the margins of the visibly active lesions and this can be helpful in distinguishing calciphylaxis from other forms of retiform purpura.
2- Cryoglobulins cause disease via two mechanisms: occlusion (type I) or immune complex- mediated vasculitis (types II, III). Simple occlusion with minimal early inflammation and often retiform purpura/necrosis develops when cryoproteins precipitate upon cold exposure, and this is primarily a reflection of monoclonal immunoglobulins (IgG, IgM ≫ IgA, light chains), i.e. type I cryoglobulinemia that is due to an underlying plasma cell dyscrasia or lymphoproliferative disorder.
Immune complex disease leads to inflammatory purpura that is palpable, and this is related to mixed cryoglobulinemia (types II or III), often due to hepatitis C viral infection.
3- In contrast, homozygous (or compound heterozygous) deficiency or severe dysfunction of either protein C or protein S leads to neonatal purpura fulminans within a few hours to 5 days after birth, and it is fatal unless treated.
4- In warfarin necrosis, the procoagulant system takes significantly longer to reach its low-point equilibrium than does the protein C-dependent anticoagulant activity. Warfarin necrosis usually develops within 2–5 days of starting warfarin in the absence of heparin, and it is much more likely to occur if loading doses of warfarin are used. A history of warfarin therapy is not mentioned in the clinical stem.
5- Subcutaneous fat necrosis is the development of one or more mobile, firm, subcutaneous nodules or plaques during the newborn period. It is sometimes associated with hypercalcemia or thrombocytopenia. Histology is characterized by granulomatous lobular panniculitis with needle- shaped clefts within lipocytes and giant cells.
- What medication causes the following lesion to erupt?
A. Metformin
B. coumadin
C. ace inhibitors
D. Indinavir
E. azathioprine
Correct choice: D. Indinavir
Explanation: Indinavir, capecitabine, systemic retinoids, hydroxyurea and GMCSF cause pyogenic granulomas to erupt.
- This rash is characterized histologically by what finding?
A. Wedge-shaped infiltrate with large cells within the infiltrate
B. Lichenoid infiltrate
C. Acanthosis and neutrophilic aggregates in the epidermis
D. Mounds of parakeratosis
E. Irregular acanthosis
Correct choice:D. Mounds of parakeratosis
Explanation: This is pitryriasis rosea which is characterized by mounds of parakeratosis histologically.
- The following clinical manifestation is most commonly seen in the setting of:
A- liver failure
B- renal failure
C- thyroid disease
D- a genetic disorder
E- obesity
Correct choice: B. renal failure
Explanation: Calciphylaxis (calcific uremic arteriolopathy): ulcers with black eschars, violaceous reticulated plaques on proximal limbs of patients with end-stage renal disease, often with hyperparathyroidism, sometimes resulting in death, calcification in small- to medium-sized blood vessels in dermis and fat, with secondary thrombosis, panniculitis, and fat necrosis.
- Immunohistochemical staining with neuron-specific enolase is positive in:
A. Anaplastic large cell lymphoma
B. Malignant firbroushistiocytoma
C. Cutaneous T cell lymphoma
D. Merkel cell carcinoma
E. Sebaceous carcinoma
Correct choice: D. Merkel cell carcinoma
Explanation: Neuron-specific enolase (NSE) is a cytoplasmic product produced by Schwann cells and neurons. This enzyme is present in neuroendocrine cells, neurons and tumors derived from them. Positive staining for NSE is found in Merkel cell carcinomas, carcinoid tumors, and malignant melanoma (among others). The remaining answer choices show negative staining with NSE.
- This lesion is characterized by dermal deposition of which material?
A. Amyloid
B. Mucin
C. Fibrin
D. Uric acid
E. Lipid
Correct choice: D. Uric acid
Explanation: Gouty tophi are formed by the deposition of monosodium urate crystals. Fibrin is found in rheumatoid nodules, and mucin is deposited in lesions of granuloma annulare.
- On histology of a eccrine ductal carcinoma there are ducts and nest of epithelial cells associated with a dense fibrous stroma. There is variable nuclear pleomorphism, mitotic activity, and are positive for CK7 and also:
A. Estrogen and progesterone receptor positive
B. CK20 positive
C. Oil red O
D. p53 positive
E. Keratin positive
Correct choice: A. Estrogen and progesterone receptor positive
Explanation: In an eccrine ductal carcinoma, the estrogen and progesterone receptor can be positive. They are often positive for CK7, CEA, negative CK20, S100 and GCDFP-15 positive.
- What is this condition?
A. Gouty Tophus
B. Sarcoid
C. Keratin granuloma
D. Rheumatoid Nodule
E. Granuloma annulare
Correct choice: A. Gouty Tophus
Explanation: Gouty Tophi occur due to an accumulation of monosodium urate in the tissues. Deposits in the dermis act as a foreign body and granulomas form around these deposits. Unless the tissue is fixed with alcohol (Carnoy’s fixative), the yellow brown crystals of gout are not well visualized on H and E. When the tissue is submitted in formalin the tophus appears pink and amorphous.Gout is diagnosed in the initial attack by using a needle and syringe to extract a small sample of fluid from around the affected joint space. MSU crystals can be identified under the microscope. This test is also important to rule out other causes of an inflamed joint, such as infection. If a biopsy sample is taken, the specimen should be placed in alcohol, as formalin dissolves urate crystals. Joint x-rays may show findings consistent with gout, but these findings are not diagnostic on their own. Furthermore, early on in the disease, x-rays may be normal or show soft tissue swelling only. Urate levels may be elevated in the blood, but this finding alone is not diagnostic. In some cases, the level may even be below urate saturation.
- Positive staining with Gross cystic disease fluid protein 15 (GCDFP-15) suggests:
A. An apocrine origin
B. An eccrine origin
C. A sebaceous origin
D. A follicular origin
E. A keratinocyte origin
Correct choice: A. An apocrine origin
Explanation: Gross cystic disease fluid protein-15 (GCDFP-15) is a commonly used apocrine marker. Gross cystic disease fluid protein-15 (GCDFP-15) is not a marker of the remaining answer choices.
- The best diagnosis is:
A. Schwannoma
B. Neurofibroma
C. Pallisaded and encapsulated neuroma
D. Perineurioma
Correct choice:C. Pallisaded and encapsulated neuroma Explanation: Pallisaded and encapsulated neuroma
- What is your best diagnosis?
A. Sebaceous Glands
B. Sebaceum
C. Lichen Planus
D. Atopic Eczema
E. Angiofibroma
Correct choice:E. Angiofibroma
Explanation: Angiofibroma is a small reddish spot or bump that consists of fibrous tissue and blood vessels. They are most commonly found around the nose, cheeks, and chin, often combining to form a distinctive butterfly-shaped pattern. Previously known as adenoma sebaceum.
- What immunohistochemical stain is most likely to be positive in this condition?
A. HPV
B. HHV-8
C. PAS
D. S100
E. Tryptase
Correct choice: E. Tryptase
Explanation: The figure illustrates lesions of urticaria pigmentosa, which stain positively for tryptase or c-kit as well as Giemsa, Leder, or toluidine blue. Patients typically present with red- brown macules or slightly raised papules which may demonstrate a positive Darier’s sign (urticaration with rubbing). HPV stain is positive in verrucae, HHV-8 is positive in Kaposi Sarcoma, PAS is positive in a variety of conditions and is helpful in visualizing dermatophytes in the epidermis, and S100 is found in a variety of conditions including melanoma.
- Which of the following is the most likely diagnosis of this image?
A. Lipoma
B. Merkel cell carcinoma
C. Metastatic adenocarcinoma
D. Melanoma
E. Myxoid neurothekeoma
Correct choice:C. Metastatic adenocarcinoma
Explanation: In this image, the lymphatics are filled with large atypical cells trying to form glands making metastatic adenocarcionma the most likely diagnosis. Merkel cell carcinoma is a sheet of blue cells with salt and pepper nuclei. A lipoma is a collection of normal fat. Melanoma would have nests of atypical melanocytes. A myxoid neurothekeoma would be a loose collection of cells in thekes with a cellular stroma and the cells do not attempt to form glands.
- What is this neoplasm?
A. Mastocytoma
B. Poroma
C. Glomus tumor
D. Langerhans cell histocytosis
E. Nevus
Correct choice:E. Mastocytoma
Explanation: Approximately 10% cases of mastocytosis present as a solitary lesion, otherwise known as a mastocytoma. Typically they present in childhood on trunk or wrist and usually are self limited and spontaneously resolve. Histologically the epidermis overlying the mast cell proliferation is often hyperpigmented. Within the dermis there are increased numbers of “fried egg” mast cells. Often the mast cells are primarily located in the upper dermis where they fill and expand the dermal papillae. Frequently admixed among the mast cells there are increased numbers of eosinophils.
- A male patient presents with hypopigmented macules on his upper back that are asymptomatic and more noticeable in the summer. What is the most likely diagnosis?
A. pityriasis rosea
B. vitiligo
C. tinea versicolor
D. eczema
E. waardenberg syndrome
Correct choice:C. tinea versicolor
Explanation: Tinea versicolor often is asymptomatic and more noticeable in the summer as patients often tan and the areas with the tinea versicolor do not tan as azeleic acid is secreted by the malassezia and melanin production is suppressed.
- On histology, this type of dermatofibrosarcoma protuberans is associated with recurrence and is regarded as a poor prognosis. It is characterized by a typical herringbone morphology of more closely packed spindled cells with increased mitosis. This best describes:
A. Bednar tumor
B. Fibrosarcomatous tumor
C. Giant cell fibroblastoma
D. Fibroblastic tumor
E. Angiodermatofibrosarcoma tumor
Correct choice: B. Fibrosarcomatous tumor
Explanation: This best describes the fibrosarcomatous type of dermatofibrosarcoma protuberans. It has a high rate of recurrence and is associated with a poor prognosis. They are also CD34+ and wide excision is recommended.
- Cellular neurothekeoma stains with:
A. Stromelysin-3
B. Desmin
C. S-100
D. PGP-9.5
E. Low molecular weight keratin
Correct choice: D. PGP-9.5
Explanation: PGP-9.5 and S100-a6 stains cellular neurothekeoma. Stromelysin-3 is positive in dermatofibromas and negative in dermatofibrosarcoma protuberans. Desmin stains rhabdomyosarcoma. S-100 stains neural tumors and melanocytic tumors among other things, but cellular neurothekeomas are generally S100-negative.
- What is the best diagnosis for this vesiculobullous disorder?
A. Bullous Pemphigoid
B. Porphyria Cutanea Tarda
C. Pemphigus vulgaris
D. Dermatitis Herpetiformis
E. Arthropod Bite
Correct choice:A. Bullous Pemphigoid
Explanation: Bullous Pemphigoid: Most common subepidermal blistering disease that frequently occurs on abdomen, groin, flexor surface of arms and legs of the elderly. In men an association with HLA-DQ7 has been seen. Often eosinophilia and elevated IgE is seen in the serum. The pathogenesis of this blistering disorder is due to binding of antibodies, IgG1 and 4 or IgE and rarely IgA, to BPAg I (230kd) and/or BP Ag II (180kd) in the hemidesmosome. Histologically there is a unilocular subepidermal blister with eosinophils. Early lesions may show eosinophilic spongiosis with papillary dermal edema. Within the dermis there is a lymphocytic eosinophilic infiltrate that is both perivascular and interstitial. DIF shows linear deposits of C3> IgG along the DEJ. Salt split skin show localization of immunoreactants in the vesicle roof. Circulating anti-BMZ antibodies are seen in 60-80% of patients but do not correlate to disease activity.
- The PDGF gene has been shown to be translocated into the collagen I gene in:
A. Angiofibroma
B. Dermatofibroma
C. Dermatofibrosarcoma protuberans
D. Fibrous hamartoma of infancy
E. Solitary fibrous tumor
Correct choice:C. Dermatofibrosarcoma protuberans
Explanation: A translocation involving the PDGF gene and collagen I gene is found in dermatofibrosarcoma protuberans.
- Which disease process best describes Texier’s disease?
A. Neutrophilic dermatosis
B. Deposition disorder
C. Infectious process
D. Panniculitis
E. Granulomatous disease
Correct choice:D. Panniculitis
Explanation: Texier’s disease is a panniculitis secondary to vitamin K injections causing sclerotic lesions with lilac borders on the buttocks and thighs resembling a cowboy belt and holster. Inflamed nodules with varying degrees of pain and fibrosis have been observed in other forms of panniculitis due to injection, with the distribution of lesions sometimes providing a clue to their cause. A dramatic example of this is Texier disease, a panniculitis due to phytonadione (vitamin K) injections. In this disorder, sclerotic lesions with lilac-colored borders form on the buttocks and thighs, in aconfiguration resembling a “cowboy gunbelt and holster”. Lesions due to blunt trauma often have an ecchymotic character andinvolve locations such as the shin, arm or hand. Hypertrichosis may also be present, possibly the consequence of local hyperemia or angiogenesis.
- What is the most likely diagnosis?
A. Wood splinter
B. suture
C. silicone
D. gel foam
E. Hyaluronic acid
Correct choice:A. Wood splinter
Explanation: Wood splinter is brown with rectangular cells. Suture is typcially a circle filled with many smaller circles. Silicone is a collection of vacoules. Gel foam is an irregularly shaped purple mass. Hyaluronic acids are just like mucin wispy and purple collections.
- This disorder is sometimes asscociated with what other symptoms?
A. Fissured tongue and facial nerve palsy
B. Shortness of breath
C. Angiomas
D. Atopic dermatitis
E. Neuroma
Correct choice:A. Fissured tongue and facial nerve palsy
Explanation: Melkersson-Rosenthal syndrome is traditionally characterized by the triad of granulomatous cheilitis, facial nerve palsy, and fissured tongue.
- Diffuse staining with this marker is suggestive of BCC rather than trichoepithelioma:
A. CAM 5.2
B. Bcl-2
C. PTAH
D. CEA
E. Cytokeratin 8
Correct choice:B. Bcl-2
Explanation: Trichoepitheliomas stains with bcl-2 on the periphery of individual tumor islands while BCC stains diffusely.
- This biopsy was obtained from an immunosuppressed patient with multiple bruise like lesions on arms and legs. What is this neoplasm?
A. Kaposi’s sarcoma
B. Lobular hemangioma
C. Targetoid hemosiderotic hemangioma
D. Tufted hemangioma
E. Angiosarcoma
Correct choice A. Kaposi’s sarcoma
Explanation: Kaposi’s Sarcoma: The vascular proliferation in all subtypes of Kaposi’s sarcoma are associated with an infection with HHV-8. Histologically early on there is a subtle proliferation of irregular angulated slit like blood vessels in dermis that dissects the collagen. When these new blood vessels encase preexisting blood vessels it’s called a promontory sign. In the stroma there is a lymphoplasmacytic infiltrate, extravasated red blood cells and hemosiderin.
Blood tests may show no abnormality, depending on whether there are associated disorders such as AIDS. Anaemia may arise if there is bleeding. KSHS assays or antibody titers to KSHS are challenging to interpret. CD4 lymphocyte counts and plasma HIV load studies are performed in patients with HIV infection. The appearance of Kaposi sarcoma lesions is often typical, but a skin biopsy of a lesion allows a definite diagnosis, as various lesions such as melanoma, fungal infections, and mycetoma mimic Kaposi sarcoma in appearance and location. The histopathology of Kaposi sarcoma shows red cells in slit-like spaces formed by atypical spindle cell proliferation of endothelial cells and associated with inflammatory cells.
- What is the diagnosis?
A. Sarcoidosis
B. Tuberculosis
C. Rosacea
D. Leprosy
E. Granulomatous leishmaniasis
Correct choice:E. Granulomatous leishmaniasis
Explanation: Long-standing lesions of chronic cutaneous leishmaniasis will often show granulomatous inflammation with scarce organisms.
- Mutations in this gene are associated with this dermatopathologic presentation:
A. PTHRP
B. c-Kit (CD117)
C. FGFR3
D. NRAS
E. TERT
Correct choice:B. c-Kit (CD117)
Explanation: Picture is of mastocyotosis pathology with positive Giemsa staining.
- A 44-year old man presents with a beefy red plaque involving the right penile shaft. Biopsy would reveal which of the following histologic findings:
A. Asteroid Bodies
B. Caterpillar Bodies
C. Cowdry Type A Bodies
D. Donovan Bodies
E. Dutcher Bodies
Correct choice D. Donovan Bodies
Explanation: Granuloma Inguinale is caused by Klebsiella granulomatis. This infection presents as a chronic suppurative infection of the genital region. Biopsy reveals Donovan bodies, which are intrahistiocyte inclusions comprised of the implicated organisms. These stain positively with both Warthin-Starry stain and Giemsa.
- Treatment of postmenopausal women with systemic conjugated estrogens has demonstrated:
A. Increased cellular atypia
B. Decreased mitotic activity of keratinocytes
C. Increased dermal collagen content
D. Decreased sebaceous gland activity
E. Increased skin laxity
Correct choice:C. Increased dermal collagen content
Explanation: Systemic use of conjugated estrogens in postmenopausal women increases total skin thickness, dermal collagen content and mitotic activity of keratinocytes. In addition, there is a reduction of dry skin, slackness and increased hydration.
- Leukocytoclastic vasculitis is typically a part of the histology of which condition?
A. Rheumatoid neutrophilic dermatosis
B. Erythema elevatum diutinum
C. Urticaria
D. Granuloma inguinale
E. Sweet’s Syndrome
Correct choice:. B . Erythema elevatum diutinum
Explanation: Erythema elevatum diutinum histologically shows a leukocytoclastic vaculitis, but with prominent interstitial neutrophils. Other conditions with evidence of LCV include IgA vasculitis, granuloma faciale, urticarial vasculitis, and occasionally serum sickness. Rheumatoid neutrophilic dermatitis is seen in the setting of severe rheumatoid arthritis. The pathogenesis is not understood, but in the few reports of this rare dermatosis, a true vasculitis has not been seen. Classically, Sweet’s syndrome also does not show evidence of a true vasculitis. LCV is not a typical histologic finding in urticaria or granuloma inguinale.
- What structure does this tumor most commonly invade?
A. blood vessels
B. hair follicle
C. nerves
D. sebaceous gland
E. arrector pili muscle
Correct choice:C. nerves
Explanation: Microcystic adnexal carcinomas typically have perineural involvement. They must be distinguished from desmoplastic trichoepitheliomas, syringomas and morpheaform BCCs.
- The pathology seen here is taken from a 68-year-old male with a diffuse skin eruption, with few blisters and crusting on the oral mucosa. Which of the followin is the most likely diagnosis?
A. Lupus erythematosus (chronic or discoid)
B. Pemphigus vulgaris
C. Tumid lupus
D. Porphyria cutanea tarda
E. Bullous pemphigoid
Correct choice:B. Pemphigus vulgaris
Explanation: The suprabasal acantholysis that extends down adnexal structures is most consistent with pemphigus vulgaris. Chronic discoid lupus and tumid lupus will have superficial and deep perivascular lymphoid infiltrates and dermal mucin.PCT will have a cell-poor subepidermal vesicle and thickening of superficial dermal blood vessels. Bullous pemphigoid will have a cell-rich subepidermal vesicle with eosinophils.
- What is the diagnosis?
A. Calciphylaxis
B. Polyarteritis nodosa
C. Leukocytoclastic vasculitis
D. Erythema nodosum
E. Cryoglobulinemia
Correct choice:A. Calciphylaxis
Explanation: Calciphylaxis: seen in patients with elevated Ca-PO4 product and secondary hyperparathyroidism most commonly patients in renal failure. Calcification occurs within the media of vessels in the lower dermis resulting in intimal hyperplasia and secondary intraluminal thrombi. Vascular occlusion then results in epidermal/dermal infarction.
A deep wedge skin biopsy may be necessary to diagnose calciphylaxis, as a similar appearance can be seen in other conditions such as necrotizing fasciitis, cryoglobulinemia, antiphospholipid syndrome, coumarin necrosis, and vasculitis. Multiple biopsies may be necessary, with a risk of propagating calciphylaxis. The pathologist looks for calcium deposited within scarred and blocked blood vessels in the subcutaneous tissue. Perieccrine calcium deposition may be noted when vascular calcification is absent but may be subtle. There may also be inflammation of the fat (panniculitis). X-rays of the affected limb may demonstrate vascular calcification within the skin; however, this may also be seen in healthy patients with renal disease that are not affected by calciphylaxis. Bone scintigraphy using technetium Tc 99m bisphosphonates in patients with calciphylaxis shows increased radiotracer uptake in soft tissues throughout the body and is specifically enhanced in indurated plaques affected by calciphylaxis (but is absent in ulcers due to reduced blood flow at sites of tissue necrosis).
- This lesion is part of the constellation of findings in which genodermatosis?
A. Neurofibromatosis I
B. Darier’s disease
C. Brooke-Spiegler syndrome
D. Cowden’s disease
E. Birt-Hogg-Dube syndrome
Correct choice:E. Birt-Hogg-Dube syndrome
Explanation: Birt-Hogg-Dube syndrome is caused by a mutation of the FLCN gene which encodes a protein called folliculin. The disorder is characterized by the presence of fibrofolliculomas, trichodiscomas, and acrochordons.
- What type of nevus is represented in this image?
A. Blue
B. Spitz
C. Dysplastic
D. Combined
E. Balloon cell
Correct choice:D. Combined
Explanation: This nevus is composed of two distinct populations of melanocytes; thus, it would be considered a combined nevus.
- This presented as a papule with a tuft of hair on the face, what is this neoplasm?
A. Trichofolliculoma
B. Trichoepithelioma
C. Fibrous Papule
D. Acrochordon
E. Fibrofolliculoma
Correct choice:A. Trichofolliculoma
Explanation: Trichofolliculoma: Most often occurs on the face as a papule with a tuft of hair. Histologically composed of a central dilated large follicle (Mama hair), from which many secondary smaller hair follicles radiate (Baby hairs), with the entire unit often enveloped in a vascularized fibrotic stroma. If sebaceous glands are associated with the hair follicles then the term used is a sebaceous trichofolliculoma or a Folliculosebaceous cystic hamartoma. Within the mesenchymal stroma there are increased CD34 and factor XIIIA fibroblasts and Merkel cells as is seen in the ORS of the follicles. Prototypically, a trichofolliculoma consists of a central cystic space with infundibular cornification and central orthokeratin. Sometimes, cross-sections of hair shafts are identifiable within the cyst. Relatively well-developed and occasionally oddly formed vellus follicles protrude in radial fashion from the central structure. The follicles usually display a bulb and papilla and exhibit inner and outer sheath and isthmic differentiation. The entire structure, including the central cyst and its associated radiating follicles, is enveloped by a vascularized fibrous (angiofibroma-like) stroma.
- Which of the following are true of reticulohistiocytoma?
A. Common in children
B. Giant cells with “ground-glass” cytoplasm
C. Association with arthritis
D. Immunostaining is positive for PTEN
E. Trauma is not a precipitating factor
Correct choice: B . Giant cells with “ground-glass” cytoplasm
Explanation: Reticulohistiocytomas, also called giant cell reticulohistiocytomas, occur almost exclusively in adults. They are generally solitary, have a ground-glass like cytoplasm and unlike the multicentric type, are not associated with mutilating arthritis or predisposition for malignancy. Trauma may be a predisposing factor, and they do not stain positively for PTEN mutations.
- A 62-year-old man presents a 1.8cm pink, friable mass on his right upper back. A full skin exam shows no other suspicious lesions and no palpable lymph nodes. A shave biopsy is done and the H+E and CK20 immunohistochemistry are shown in the images. Which of the following is the best treatment to proceed with next?
Correct choice:D. Wide local excision with sentinel lymph node biopsy
Explanation: The clinical and pathological findings are consistent with a Merkel cell carcinoma. The preferred treatment for a tumor on the trunk without clinically apparent lymphadenopathy is wide local excision (1-3 cm margins) and sentinel lymph node biopsy. If the lymph node biopsy is
positive, then the patient will likely require radiation therapy. For lesions >2cm, some clinicians will not perform a sentinel lymph node biopsy since radiation therapy is indicated regardless, given the high risk of lymph node metastasis.
- Supporting evidence for the diagnosis of mycosis fungoides is CD4+ lymphocytes with loss of CD7 as well as loss of
A. CD27
B. CD68
C. CD5
D. CD20
E. CD30
Correct choice:C. CD5
Explanation: CD5 as well as CD7 are sometimes lost on the surface of epidermotropic T cells in mycosis fungoides. CD2, CD3, and CD5 are T cell markers. CD20 is a B cell marker. CD30 is positive in anaplastic large cell lymphoma cells, Hodgkins lymphoma, and lymphomatoid papulosis. Reactive infiltrates can also have some CD30-positive cells. CD68 marks histocytes.
- Which of the following immunostains would be positive in primary cutaneous amyloid?
A. Cytokeratin 5
B. Cytokeratin 15
C. Melanoma Antigen Recognized by T cells 1
D. CD-31
E. CD-57
Correct choice: A. Cytokeratin 5
Explanation: The amyloid deposits in primary cutnaeous amyloid are derived from keratin intermediate filament proteins. Degeneration of basal keratinocytes in the overlying epidermis likely play a strong role. In one theory, cytokeratin released from apoptotic basal keratinocytes form the amyloid fibrils. Pathology specimens from primary cutaneous amyloid stain positive for cytokeratin 5. The other listed immunostains are not positive in primary cutnaeous amyloid.
- The organism on this slide stained with Warthin-Starry is responsible for what disease?
A. Bacillary Angiomatosis
B. Cellulitis
C. Madura foot
D. Pyoderma gangrenosum
E. Pyogenic granuloma
Correct choice:A. Bacillary Angiomatosis
Explanation: Bacillary (epithelioid) angiomatosis is caused by Bartonella Henselae or Bartonella quintana (trench fever- from body louse). Clinically resembles PG but multiple lesions and in a HIV+ patient, usually with history of exposure to cats. Histologically there is dome shaped lesion with an epidermal collarette with a proliferation of reactive plump blood vessels similar to a PG, but the lesion is less lobular and there is PMNs and dust throughout the lesion along with extracellular clumps of purplish gram ‚¬â€œ bacilli. The organism is + for Warthin-Starry, which highlights the organisms in a characteristic Chinese letter configuration.
- This patient has a black toenail. What is the diagnosis?
A. Medication deposition
B. Tattoo
C. Ungual melanoma
D. Tinea unguium
E. Intraungual hematoma
Correct choice: E. Intraungual hematoma
Explanation: Intraungual hematoma can develop as a result of trauma and can appear black on clinical exam. A histologic examination will show blood within the nail plate.
- What is this lesion?
A. Hidradenoma
B. Spiradenoma
C. Dermal duct tumor
D. Trichoepithelioma
E. Chondroid syringoma
Correct choice:E. Chondroid syringoma
Explanation: Chondroid syringomas (mixed tumors) are well-circumscribed dermal nodules demonstrating epithelial cords and ductal structures in a myxoid, chondroid and fibrous stroma.
- These lesions (hint: double-walled) typically occur on which part of the body?
A. Face
B. Hands
C. Mucosa
D. Legs
E. Scalp
Correct choice: A. Face
Explanation: Hidrocystomas are cysts lined by a double layer of epithelial cells. They most commonly occur on the face but can occur in other areas as well.
- What does this show on histopathology?
A. Massive dermal edema with telangiectasias and a lichenoid infiltrate below the dermal edema
B. Interface dermatitis
C. Lichenoid dermatitis
D. Loose myxoid collagen
E. Squared off biopsy with thick collagen, decreased adnexal structures and entrapped eccrine glands higher up in the dermis
Correct choice: E. Squared off biopsy with thick collagen, decreased adnexal structures and entrapped eccrine glands higher up in the dermis
Explanation: This is morphea which is characterized by a squared off biopsy with dense fibrotic collagen, decreased adnexal structures and entrapped eccrine glands higher up in the dermis.
- All of the following are true regarding smooth muscle hamartomas except:
A. Hyperpigmentation
B. Transient piloerection
C. Hypertrichosis
D. Association with “Michelin tire baby” in females
E. Becker’s nevus syndrome is an example
Correct choice: D. Association with “Michelin tire baby” in females
Explanation: Smooth muscle hamartomas of the skin may develop from three locations: the arrector pili muscles, blood vessel walls, and genital/areolar skin. The have been associated with hyperpigmentation, tranisent piloerection (“pseudo-Darier’s sign”) and hypertrichosis. It is thought to be the underlying lesion in “Michelin tire baby” syndrome in boys, not girls.
- Which of the following entities can prove difficult to diagnose on H+E histology, as it can appear with similar features to erythema multiforme?
A. Erythema elevatum diutinum
B. Lichen planus pigmentosus
C. Paraneoplastic pemphigus
D. Pemphigus erythematosus
E. Zoon’s balanitis
Correct choice: C. Paraneoplastic pemphigus
Explanation: In paraneoplastic pemphigus, there is usually an overt interface or lichenoid infiltrate associated with necrotic keratinocytes at all levels of the epidermis which can closely resemble erythema multiforme. In addition, foci of suprabasal acantholysis are seen. Direct immunofluorescence usually shows intercellular and basement membrane deposition of IgG and C3. The other listed entities do not appear as similar to EM on H+E.
- The predominant location of the cleft in acropustulosis of infancy is:
A. Dermal
B. Basment mebrane zone
C. Basal keratinocytes
D. Suprabasal
E. Subcorneal/granular
Correct choice: E. Subcorneal/granular
Explanation: Acropustulosis of infancy presents as idiopathic pustules on acral skin. Diagnosis is made only after other causes of pustules have been ruled out, and it usually resolves in a few years. The cleft in acropustulosis of infancy is subcorneal/granular with neutrophils.The other listed levels of split are not accurate.
- A patient presents to you for an initial consultation of hair loss. You explain that hair disorders may affect various levels of the hair follicle. What are the layers of the lower portion of the hair follicle from outer to inner?
A. Fibrous root sheath, vitreous layer, outer root sheath, inner root sheath (Henle, Huxley, cuticle of inner root sheath), hair cuticle, hair cortex, hair medulla
B. Fibrous root sheath, vitreous layer, outer root sheath, inner root sheath (Huxley, Henle, cuticle of inner root sheath), hair cuticle, hair cortex, hair medulla
C. Fibrous root sheath, vitreous layer, outer root sheath, inner root sheath (Henle, Huxley, cuticle of inner root sheath), hair cortex, hair medulla, hair cuticle
D. Fibrous root sheath, outer root sheath, inner root sheath (Henle, Huxley, cuticle of inner root sheath), vitreous layer, hair cuticle, hair cortex, hair medulla
E. Vitreous layer, outer root sheath, inner root sheath (Henle, Huxley, cuticle of inner root sheath), hair cuticle, hair cortex, hair medulla, fibrous root sheath
Correct choice: A. Fibrous root sheath, vitreous layer, outer root sheath, inner root sheath (Henle, Huxley, cuticle of inner root sheath), hair cuticle, hair cortex, hair medulla
Explanation: The layers of the lower portion of the hair follicle from outer to inner are: fibrous root sheath, glassy/vitreous layer, outer root sheath, inner root sheath (Henle, Huxley, cuticle of inner root sheath), hair cuticle, hair cortex, hair medulla
- From what cell is this deposition derived?
A. Lymphocyte
B. Melanocyte
C. Sebocyte
D. Keratinocyte
E. Macrophage
Correct choice:D. Keratinocyte
Explanation: This is macular amyloid which is keratinocyte derived and due to chronic rubbing. The other listed cells do not contribute to macular amyloid
- These biopsy findings are most likely related to which compound?
A. Silver
B. Gold
C. Amiodarone
D. Minocycline
E. Topical hydroquinone
Correct choice:E. Topical hydroquinone
Explanation: Exogenous ochronosis is most frequently seen after long-term application of topical hydroquinone compounds. On pathology, there are large yellow-brown ‘banana-shaped’ deposits in the dermis. Identical findings can be seen in alkaptonuria, which can cause an endogenous ochronosis. Alkaptonuria is caused by an autosomal recessive deficiency of homogentisic acid oxidase.
- Which form of calcinosis cutis would describe calcinosis scroti?
A. Idiopathic
B. Metastatic
C. Dystrophic
D. Iatrogenic
E. Autoimmune
Correct choice:A. Idiopathic
Explanation: Localized calcium deposition frequently occurs idiopathically on the scrotum, penis, or vulva. Metastatic calcification occurs in the setting of abnormal calcium or phosphorus metabolism. Dystrophic calcification occurs in areas of trauma or other damage to tissue. Iatrogenic calcification occurs secondary to a treatment or procedure.
- What is the diagnosis?
A. Dermatofibrosarcoma
B. Nodular fasciitis
C. Angiolipoma
D. Epithelioid sarcoma
E. Liposarcoma
Correct choice:C. Angiolipoma
Explanation: Angiolipomas are tumors of fat that are characteristically painful. Histopathologically, mature adipocytes are seen with numerous vessels. Microthrombi are often present. The other answer choices do not have the pictured histopathological findings.
- Histologic examination of cutaneous metastases from breast cancer is likely to demonstrate:
A. Dense lymphocytic infiltration
B. Tumors cells perivascularly
C. Eosinophilia
D. Tumor cells in the lymphatics
E. Band-like dermal infiltrate
Correct choice:D. Tumor cells in the lymphatics
Explanation: Histologic appearance of metastatic breast carcinoma to the skin typically shows tumor cells in linear arrangement in so-called “Indian-filing” pattern. These tend to occur in the dermis and subcutaneous lymphatics. Extensive lymphatic dissemination may be caused by retrograde lymphatic spread. The tumor cells are large, pleomorphic with hyperchromatic nuclei.
- Mulberry cells contain increased:
A. Phagolysosomes
B. Mitochondria
C. Golgi
D. Ribosomes
E. Phagolysosomes and mitochondria
Correct choice: B. Mitochondria
Explanation: Hibernomas commonly arise in the neck, axillae, and posterior shoulder. The cells are multivacuolated and resemble mulberries; the cells are filled with mitochondria, as are the cells in normal brown fat. The mulberry cells in hibernomas do not contain the other listed organelles.
- A focal non-Langerhans cell histiocytosis with Touton giant cells is seen in a child with Neurofibromatosis Type I. The patient has an increased risk of which of the following conditions?
A. Glaucoma
B. Acute myeloid leukemia
C. Juvenile myelomonocytic leukemia
D. Atrial myxoma
E. Ocular hypertelorism
Correct choice: C. Juvenile myelomonocytic leukemia
Explanation: The described lesion is a Juvenile Xanthogranuloma, which is the most common non- langerhans cell histiocytic neoplasm. These usually affect children and are found in the head and neck area. Touton giant cells are a characteristic histologic finding. There is a vastly increased risk of developing Juvenile myelomonocytic leukemia (choice 3) in patients with JXG and NF1, thought to be due to the RAS oncogene being affected. Ocular JXG may be associated with glaucoma or blindness and thus remains an important entity, but glaucoma risk is not increased with cutaneous
JXG. There is no increased risk of AML. Atrial myxoma are seen in NAME/LAMB syndrome. Ocular hypertelorism is seen in LEOPARD syndrome.
- Pustulo-ovoid bodies of Milian can be found associated with which of the following conditions?
A. Granular cell tumor
B. Leishmaniasis
C. Schwannoma
D. Chromomycosis
E. Rhinoscleroma
Correct choice: A. Granular cell tumor
Explanation: Pustulo-ovoid bodies of Milian can be seen in association with granular cell tumors. They appear as relatively large and eosinophilic intracytoplasmic inclusions with a surrounding clear halo. These inclusions characteristically stain positive with PAS and are diastase resistant. Leishmaniasis is associated with leishman-Donovan bodies, which are intracytoplasmic basophilic organismal (amastigotes) inclusions found in parasitized histiocytes. Verocay bodies may be seen in schwannomas, which appear as pallisaded nuclei in rows. Medlar bodies (“copper pennies”) can be seen in cutaneous infectious of chromomycosis and appear as grouped ovoid spores measuring 6 to 12 micrometers both within histiocytes as well as interstitially. Russell bodies are associated with rhinoscleroma and are elliptical basophilic inclusions found in plasma cells and are comprised of immunoglobulins.
- What HPV strain causes this lesion?
A. HPV 2
B. HPV 6
C. HPV 5
D. HPV 7
E. HPV 1
Correct choice: E. HPV 1
Explanation: Myrimecial warts are endophytic growths on the soles of the feet. They are caused by HPV 1. There are numerous eosinophilic inclusions within the keratinocytes.
- Biopsy of this lesion reveals a poorly-defined dermal mass of small blue monomorphic round cells with scant cytoplasm and nuclear molding. Which histologic stain is most helpful in distinguishing this lesion from small cell lung carcinoma.
A. CK20
B. TTF-1
C. Chromogranin
D. Synaptophysin
E. Somatostatin
Correct choice:B. TTF-1
Explanation: The pictured image is that of merkel cell carcinoma (MCC), a rare highly aggressive malignant neuroendocrine carcinoma. In order to differentiate MCC from small cell lung carcinoma
(SCLC; aka Oat cell carcinoma), another malignant neuroendocrine carcinoma, histologic staining with TTF-1 is most helpful. This is because MCC (nearly always) stains negative for TTF-1, whereas SCLC stains positive for TTF-1. The remaining answer choices will be positive in both MCC and SCLC, so they cannot be used to differentiate between the two malignancies.
- A 40-year-old man presents with many skin-colored papules of the face. He thinks that his grandfather may have had the same condition. A representative skin lesion is biopsied for further evaluation. Which pilar neoplasm is histologically characterized as a fibrous pink or amphophilic fibromucinous orb, no hair fibers, and epithelial strands radiating outward from a central follicle- like structure?
A. Fibrofolliculoma
B. Trichoepithelioma
C. Pilomatricoma
D. Trichofolliculoma
E. Trichoadenoma
Correct choice:A. Fibrofolliculoma
Explanation: In fibrofolliculomas, the strands of epithelium are not well enough differentiated to form hair fibers. No bulb, inner or outer root sheath is present. The strands of epithelium may have an anastomosing pattern. Histolocially there are epithelial strands radiating outward from a central follicle-like structure, no hair fibers, and a fibrous pink or amphophilic fibromucinous orb.
Trichoepithelioma: A trichoepithelioma is a blue tumor composed of basaloid cells and is a distinctive type of trichoblastoma. At scan, it has finger-like projections and cribriform nodules. The stroma resembles the normal fibrous sheath of the hair follicle, with concentric collagen and many fibroblasts. Papillary mesenchymal bodies are prominent. Mucin may be present within cribriform tumor islands, but never within the stroma.
Pilomatricoma: A pilomatricoma appears as a large ball with internal trabeculae and is characterized by basophilic cells that resemble those of the hair matrix which keratinize to form shadow cells. There is often calcification and bone formation.
Trichofolliculoma: A trichofolliculoma demonstrates miniature follicles converging on a central infundibulum embedded in an eosinophilic fibrous orb or stroma.
Trichoadenoma: A trichoadenoma is a pilar neoplasm histologically characterized by multiple red doughnuts in the dermis, each resembling a follicular infundibulum, often in pairs resembling eyeglasses or toasted oat cereal.
- The mutation in the syndrome that is most associated with this lesion is which of the following?
A. PTCH
B. APC
C. MSH2
D. PTEN
Correct choice D. PTEN
Explanation: Cowden’s syndrome is a mutation in PTEN and is associated with tricholemmomas and breast, thyroid and GI carcinoma. They also get acral keratoses and palmar pits and lipomas.
- What is the most likely diagnosis for this single lesion?
A. wart
B. hailey hailey
C. dariers
D. pemphigus vegetans
E. Warty dyskeratoma
Correct choice: E. Warty dyskeratoma
Explanation: Warty dyskeratoma is a cup-shaped invagination with acanthlytic and dyskeratosis. Both hailey hailey and darier’s do not have this architecture. Hailey hailey has more acantholysis, dariers has more dyskeratosis, and both are larger plaques. It would be unusal to have one single lesion of hailey hailey, dairers or pemphigus vegetans.
- A 6-month old infant develops tense blisters on the distal extremities which develop on normal- appearing skin. He has a neurologic disease and has been immobilized for a long period of time. The blisters spontaneously heal within 1-2 weeks. You suspect a diagnosis of coma bullae. Which of the following is the key characteristic histologic feature that would assist you in making this diagnosis?
A. Necrosis of sweat glands
B. Intraepidermal bullae
C. Subepidermal bullae
D. Pronounced inflammatory cell infiltrate
E. Positive direct immunofluorescence for IgG and C3
Correct choice: A. Necrosis of sweat glands
Explanation: Coma bullae are predominantly subepidermal. However, intraepidermal blisters are also observed as the result of re-epithelialization of older lesions or epidermal spongiosis. There is a variable degree of epidermal necrosis. Sweat gland necrosis is a characteristic finding, and focal necrosis of the epithelium of the pilosebaceous follicles can also be seen. There is only a sparse inflammatory cell infiltrate. DIF is usually negative, but deposits of IgG, IgM and/or C3 have been found within the walls of dermal blood vessels.
- Biopsy of a mucosal neuroma from a patient with MEN IIb looks histologically like a:
A. Neurilemmoma
B. Neurofibroma
C. Palisaded encapsulated neuroma
D. Traumatic neuroma
E. Neurothekeoma
Correct choice: C. Palisaded encapsulated neuroma
Explanation: Mucosal neuromas in MEN IIb often look histologically like PENs. Occasionally mucosal neuromas display thickened nerves/perineurium.
The other listed entities do not typically share the same features as mucosal neuromas in MEN.
- What immunohistochemical stain is most likely to be positive in this condition?
A. HPV
B. HHV-8
C. PAS
D. S100
E. Tryptase
Correct choice: E. Tryptase
Explanation: The figure illustrates lesions of urticaria pigmentosa, which stain positively for tryptase or c-kit as well as Giemsa, Leder (chloroacetate esterase), or toluidine blue. Patients typically present with red-brown macules or slightly raised papules which may demonstrate a positive Darier’s sign (urticaration with rubbing). HPV stain is positive in verrucae; HHV-8 is positive in Kaposi Sarcoma. PAS is positive in a variety of conditions and is helpful in visualizing dermatophytes in the epidermis, and S100 is found in a variety of conditions including melanoma.
- A deposition of what substances leads to these deposits?
A. Homogentisic acid
B. Amyloid
C. Fungal organisms
D. Colloid
E. Tattoo
Correct choice: A. Homogentisic acid
Explanation: Ochronosis: can be either endogenous or exogenous. The endogenous form is due to an AR defect in homogentisic acid oxidase, which prevents tyrosine and phenylalanine from being degraded beyond homogentisic acid. The exogenous form of ochronosis, on the other hand, occurs from topical hydroquinone, mercury resorcinol, phenol, picric acid or benzene, or systemic quinine or chloroquine which all inhibits homogentisic oxidase and leads to a focal accumulation of homogentisic acid. Within the superficial dermis there are irregular shaped elongated yellow deposits which have been described as as bananas in the dermis that occur due to deposition of homogentisic acid on the collagen.
- In children with pernio, what may be associated?
A. cryoglobulins
B. diabetes
C. lupus
D. calcinosis cutis
E. osteoma cutis
Correct choice: A. cryoglobulins
Explanation: In kids, pernio can be associated with cryoglobulins and cold agglutinins. It is triggered by cold and wet which results in acral violaceous color with burning and itching.
- In which condition are Gamma-Favre bodies seen?
A. Granuloma inguinale
B. Lymphogranuloma venereum (LGV)
C. Syphilis
D. Chancroid
E. Herpes virus
Correct choice: B. Lymphogranuloma venereum (LGV)
Explanation: LGV is a sexually transmitted disease that is characterized by suppurative inguinal adenitis with matted lymph nodes, inguinal bubo with secondary ulceration, and constitutional symptoms. It is caused by Chlamydia trachomatis serotypes L1, L2, and L3. First line treatment is doxycycline 100mg bid for 3 weeks as well as treating the sexual partners. Gamma-Favre bodies are found in histiocytes in LGV.
- This tumor is vimentin+ and cytokeratin+:
A. Angiosarcoma
B. Neurothekeoma
C. Nodular fasciitis
D. Dermatofibroma
E. Epithelioid sarcoma
Correct choice: E. Epithelioid sarcoma
Explanation: Characteristic immunohistochemistry of epithelioid sarcoma is vimentin and cytokeratin positivity. The other listed tumors do not stain both vimentin+ and cytokeratin+.
- This disorder is characterized by what process?
A. Vascular damage caused by infiltration of neutrophils
B. Vascular fragility
C. Large vessel involvement
D. Delayed-type hypersensitivity reaction
E. The presence of amyloid
Correct choice: A. Vascular damage caused by infiltration of neutrophils
Explanation: Leukocytoclastic vasculitis is characterized by vascular damage caused by the infiltration of neutrophils
72-Biopsy of this lesion shows palisading of histiocytes around a focus of necrobiosis and increased mucin deposition in the upper dermis. Lymphocytes and fibroblasts are present around the palisades as well. What is the most likely diagnosis?
- Cutaneous sarcoidosis
- Rheumatoid nodule
- Cutaneous tuberculosis
- Necrobiosis lipoidica
- Granuloma annulare
Correct choice: E. Granuloma annulare
Explanation: Granuloma annulare (GA) typically presents as an annular, pink/red to violaceous, non-scaly papule or plaque on the dorsal hands or feet. The classic biopsy findings for GA include: mid dermal necrobiotic collagen center surrounded by palisading histiocytes, as well as fibroblasts and lymphocytes; occasional foreign body giant cells, vasculitis and mucin. It is important to note that other variants of GA (subcutaneous, interstitial, perforating) show a different histopathologic picture.
Cutaneous sarcoidosis may present as a clinical mimic of GA, but biopsy typically shows “naked” histiocytic collections (i.e. no surrounding lymphocytes) in the dermis without increased mucin deposition. Biopsy of a rheumatoid nodule usually reveals fibrin deposition and necrobiosis often seen in center of nodule surrounded by well developed palisading of histiocytes, vascular granulation tissue, lymphocytes, plasma cells, eosinophils, variable giant cells, fibrosis in older lesions, occasional giant cells. It is important to note that these findings are seen typically in subcutaneous fat or soft tissue, although may extend to deep reticular dermis, whereas granuloma annulare has more superficial findings. Cutaneous tuberculosis is distinguished from GA by the presence of histiocytes surrounding areas of caseation necrosis, as well as the presence of acid-fast bacilli. Lastly, necrobiosis lipoidica most often presents as atrophic, yellow depressed plaques with telangiectasias and active inflammatory edges on the bilateral pretibial areas. A biopsy will show palisading, necrobiotic granulomas consisting of a large confluent area of necrobiosis centered in the superficial dermis and subcutaneous fat (this arrangement has been likened to the appearance of a “layered cake”).
- Where is the classic location of this lesion?
A. Ear
B. Back
C. Leg
D. Along the milk line
E. Dorsal hand
Correct choice: D. Along the milk line
Explanation: This is an accessory nipple. You can see the ducts and the smooth muscle as well as the papillomatous epidermis. It is most commonly located on the trunk along the milk line.
- Which blistering disorder clinically and histologically appears as non-inflammatory bullae?
A. Porphyria cutanea tarda
B. Bullous pemphigoid
C. Pemphigus vulgaris
D. Linear IgA bullous dermatosis
E. Bullous lupus erythematosus
Correct choice: A. Porphyria cutanea tarda
Explanation: PCT clinically and histologically presents as non-inflammatory bullae.
- This neoplasm occurs most frequently in what anatomic location?
A. Leg
B. Mucosa
C. Acral
D. Head and neck
E. Trunk
Correct choice: D. Head and neck
Explanation: Desmoplastic melanoma is spindle cell variant of malignant melanoma. It typically occurs in the head and neck region in older individuals. It demonstrates a high recurrence rate but lower rates of metastasis.
- A four-year-old boy presents with a subcutaneous nodule on his cheek which often becomes inflamed and red. This neoplasm (shown in photo) has demonstrated mutations in which gene product, which is a component of a key signaling pathway that influences cell differentiation and proliferation?
A. B-catenin
B. P53
C. Smoothened
D. Rb
E. PTCH
Correct choice: A. B-catenin
Explanation: Pilomatricoma is a benign neoplasm that demonstrates mutations in CTNNB1, the gene that encodes B-catenin, a component of a key signaling pathway that influences cell differentiation and proliferation and is generally present in matrical neoplasms. Pilomatricomas present as a cyst with basaloid matrical cells that show an abrupt transition to central eosinophilic, cornified matrical cells in which barely discernible nuclear outlines remain. Sometimes pink trichohyaline granules are identified at transition points. Central anucleate cornified cells are referred to as “ghost” or “shadow” cells.
2 – P53 is a tumor suppressor gene and functions primarily as a transcription factor. It is not involved in pilomatricomas. 3 – Smoothened is a protein that is encoded by the SMO gene. It is a
class Frizzled G protein-coupled receptor that is a component of the hedgehog signaling pathway. Mutations in SMO are detected in sporadic basal cell carcinomas in which PTCH1 is intact. 4 – Rb gene encodes the retinoblastoma protein, a tumor suppressor protein that is dysfunctional in several major cancers. One function of Rb is to prevent excessive cell growth by inhibiting cell cycle progression until a cell is ready to divide. 5 – PTCH is a tumor suppressor gene that is involved in basal cell carcinoma. Inactivating mutations in PTCH lead to dysfunctional Patched and this stimulates Hedgehog binding and results in constitutive activation in downstream target genes.
- The organisms highlighted by this GMS stain are?
A. Blastomycosis
B. Coccidioidomycosis
C. Mucormycosis
D. Candida albicans
E. Histoplasmosis capsulatum
Correct choice: A. Blastomycosis
Explanation: Blastomycosis: Gilchrist disease, Bird droppings or spores on wood along Mississippi basin, incubation 33-44 days. Most infections develop in previously healthy people. In patients with HIV, 46% will get CNS symptoms, which is 5-10x greater than non-HIV pts. 4 forms, pulmonary, disseminated (CNS, bone, skin and GU) with secondary cutaneous lesions and primary inoculation (rare-1-2 weeks after exposure-sporotrichoid pattern- mixed infiltrate numerous budding organisms). Lesions more typically are verrucous or ulcerated plaques in males on exposed skin- face. Histology: Pseudoepitheliomatosis hyperplasia overlying acute dermal inflammation usually only a few organisms in center of abscess with thick walled 7-15 microns, single broad based bud, has a WI-1 adhesion protein and are best seen with PAS or GMS.
Histologic examination of skin lesions demonstrates pseudoepitheliomatous hyperplasia, suppurative and granulomatous inflammation, and round yeast forms with characteristic broad- based budding and thick, double-contoured walls. This budding pattern helps to differentiate blastomycosis from other fungal infections. Methenamine silver and PAS staining allow better visualization of the fungi within giant cells and neutrophilic abscesses. Similar budding yeast forms can be seen in sputum samples.
- What is the diagnosis of this neoplasm in infants?
A. Infantile hemangioperictyoma
B. Tufted angioma
C. Kaposiform hemangioendothelioma
D. Dermatomyofibroma
E. Giant cell fibroblastoma
Correct choice: A. Infantile hemangioperictyoma
Explanation: Infantile hemangiopericytomas are benign lesions. They are multilobulate, with perivascular and intravascular tumors outside the main tumor mass.
- On which anatomic location does this neoplasm typically occur?
A. Scalp
B. Lower legs
C. Arms
D. Oral mucosa
E. Trunk
Correct choice: B. Lower legs
Explanation: Clear cell acanthomas tend to occur on the lower legs of middle-aged or and elderly individuals.
- What is the most likely diagnosis?
A. Steatocystoma
B. Epidermoid inclusion cyst
C. Eccrine Hidrocystoma
D. Bronchogenic cyst
E. Thyroglossal cyst
Correct choice: C. Eccrine Hidrocystoma
Explanation: This is an eccrine hidrocystoma (choice 3) as evidenced by the two layers of cuboidal epithelium with eosinophilic cytoplasm. A steatocystoma typically has a “shark fin” cuticle. An epidermoid cyst approximates the layers of the normal epidermis. Bronchogenic cysts have a respiratory, ciliated lining. A thyroglossal cyst typically has pseudostratified columnar epithelium and lymphoid follicles.
- Treatment of a patient with chronic venous ulceration is best achieved by which modality?
A. endovenous laser ablation
B. ambulatory phlebectomy
C. sclerotherapy
D. observation
E. surgical excision and debridement
Correct choice: A. endovenous laser ablation
Explanation: Venous stasis ulcers often occur due to an incompetent superficial venous system which creates pooling of blood in the ankles. Treatment of the atypical greater saphenous vein with endovenous laser ablation, removes the atypical veins allowing the blood to return to the heart in the deep system, relieveing the pressure in the venous system and thus allows the venous ulceration to heal.
- A lesion with the same pathology as in the photograph is located on the patient’s penis. What is the name for these penile lesions?
A. Pearly penile papules
B. Warts
C. Montgomery’s tubercles
D. Glands of Zeis
E. Moll’s glands
Correct choice: A. Pearly penile papules
Explanation: The pathology shows an angiofibroma. Angiofibromas on the penis are specifically called pearly penile papules and are benign. The patient should be reassured.
- Which of the following is commonly seen histopathologically in pityriasis rosea?
A. Absent spongiosis
B. Full thickness necrosis
C. Exravasated erythrocytes in the subcutaneous fat
D. Lichenoid lymphocytic infiltrate
E. Focal parakeratosis
Correct choice: E. Focal parakeratosis
Explanation: Histopathological features of Pityriasis Rosea include: mild subacute spongiotic dermatitis, focal parakeratosis (corresponds to cigarette paper-like scale), perivascular lymphocytic infiltrate, hemorrhage in papillary dermis, and sometimes a few necrotic keratinocytes. The other answer choices are not commonly seen histopathologically in pityriasis rosea.
- What is the most common symptom of this tumor?
A. Tingling
B. No symptoms
C. Itching
D. Burning
E. Pain
Correct choice: E. Pain
Explanation: This is an angiolipoma, one of the painful tumors. It is most commonly located on the forearm and occurs in men more then women. Histologically you see mature lipocytes with numerous thrombosed vessels.
- In this disorder, colloid bodies are composed of which material?
A. Fibrin
B. T-cells
C. Apoptotic keratinocytes, IgM, and complement
D. Langerhans cells
E. Basement membrane
Correct choice: C. Apoptotic keratinocytes, IgM, and complement
Explanation: Colloid bodies are composed of apoptotic keratinocytes, IgM, and complement.
- Psoriasis has been shown to be genetically linked to:
A. Pityriasis rosea
B. Clear cell acanthomas
C. Epidermodysplasia verruciformis
D. Verruciform xanthomas
E. Poromas
Correct choice: C. Epidermodysplasia verruciformis
Explanation: Mutations have been found in the EVER1 and EVER2 genes in epidermodysplasia verruciformis; these genes are on 17q25, the location of the PSORS2 gene (one of the genes implicated in the inheritance of psoriasis).
- Psoriasis vulgaris may demonstrate all except one of the following histopathologic changes.
A. Munro microabscesses
B. Clubbing of the rete ridges
C. Spongiform pustules of Kogoj
D. Hypergranulosis
E. Suprapapillary thinning
Correct choice: D. Hypergranulosis
Explanation: Psoriasis is characterized by confluent parakeratosis (not focal); hyperkeratosis; neutrophils in stratum corneum (Munro microabscesses) and in spinous layer (spongiform pustules of Kogoj); hypogranulosis; suprapapillary thinning of epidermis (epidermis is very thin over dermal papillar; regular acanthosis (rete ridges about same length), often with clubbed rete ridges; dilated
capillaries in dermal papillae (causes Auspitz sign of pinpoint bleeding if scale picked off); perivascular lymphocytes.
- Which of the following stains with Ulex europeus agglutinin I?
A. Smooth muscle
B. Eccrine glands
C. Endothelial cells
D. Macrophages
E. Melanocytes
Correct choice: C. Endothelial cells
Explanation: Ulex europeus agglutinin I is a stain which identifies endothelial cells, keratinocytes, angiosarcomes and Kaposi’s sarcoma.
- What is the best description of the histopathology expected for the border of the lesion seen here?
A. Regular elongated rete ridges with superficial small vessels
B. Epidermal spongiosis with atypical lymphocytes spreading into the epidermis
C. Perivascular lymphocytic infiltrate with prominent eosinophils
D. Hyperplasia of the superficial epidermis
E. Parakeratosis in a column over focal dyskeratotic or vacuolated keratinocytes
Correct choice: E. Parakeratosis in a column over focal dyskeratotic or vacuolated keratinocytes
Explanation: This is an image of porokeratosis. While the center of the lesion can have variable histopathology (mild spongiosis or psoriasiform dermatitis), the raised border is represented histologically with a column of parakeratosis over often dyskeratotic or vacuolated keratinocytes.
Regular elongated rete ridges is seen in psoriasis. Epidermal spongiosis with atypical lymphocytes spreading into the epidermis can be seen in mycosis fungoides. Perivascular lymphocytic infiltrate with prominent eosinophils can be seen with DRESS syndrome or other drug eruptions. Hyperplasia of the superficial epidermis can be seen in other benign epidermal tumors.
- What is the diagnosis?
A. Pigmented purpuric dermatosis
B. Livedoid vasculopathy
C. Hematoma
D. Leukocytoclastic vasculitis
E. Thrombotic vasculopathy
Correct choice: C. Hematoma
Explanation: A hematoma is defined by the presence of extravasated erythrocytes.
- This type of lupus completely spares the epidermis.
A. acute cutaneous lupus
B. discoid lupus
C. chronic cutaneous lupus
D. chilblains lupus
E. tumid lupus
Correct choice E. tumid lupus
Explanation: Tumid lupus completely lacks any interface dermatitis and the epidermis is completely spared. It is the most photosensitive of all the lupus types. There is lots of mucin on biopsy.
- Which of the following types of acrospiroma consists of a variable composition of poroid, squamoid, clear cells with ductal areas, may be solid/cystic, and is based in the deeper dermis?
A. Hidroacanthoma simplex
B. Poroma
C. Dermal duct tumor
D. Hidradenoma
E. None of the above
Correct choice: D. Hidradenoma
Explanation: Acrospiromas include hidroacanthoma simplex (located intraepidermally), poroma, dermal duct tumor, hidradenoma (deeper dermis). A hidradenoma has a variable composition of poroid, squamoid, clear cells with ductal areas; may be solid/cystic; and is based deeper in the dermis than the other lesions listed.
- A grenz zone is seen in which of the following conditions?
A. Granuloma faciale
B. Polyarteritis nodosa
C. Telogen effluvium
D. Sweet’s syndrome
E. Erythema ab igne
Correct choice A. Granuloma faciale
Explanation: Granuloma faciale overlies a mix of neutrophils, eosinophils, lymphocytes, histiocytes. GF often presents clinically as a reddish brown macule or plaque. It is characterized by a Grenz zone with leukocytoclastic vasculitis with eosinophils benath this. Onion skin fibrosis can be seen in chronic cases. Grenz zone differential: Lepromatous leprosy, cutaneous B cell lymphoma, Chronic lymphocytic leukemia/small lymphocytic lymphoma, acute myelomonocytic Leukemia, leiomyosarcoma, and Botryoid rhabdomyosarcoma.
- A 55 year old male presents for evaluation of a slowly growing subcutaneous nodule on his posterior neck. What is the most likely diagnosis?
A. Spindle cell lipoma
B. Angiolipoma
C. Piloleiomyoma
D. Metastatic adenocarcinoma
E. Cytophagic histiocytic panniculitis
Correct choice: A. Spindle cell lipoma
Explanation: This is a spindle cell lipoma (choice 1). These demonstrate “rope-like” collagen, myxoid stroma, spindle-cells, mast cells, and mature fat. Angiolipoma show many blood vessels. Piloleiomyoma is a tumor of muscle, which is not pictured. Adenocarcinoma would show “indian- filing” of cells. Cytophagic histiocytic panniculitis shows macrophages phagocytizing other cells, and characteristic “bean bag cells.”
- A middle-aged man presents with many 2-3 mm, firm, waxy closely aligned papules in a widespread symmetrical pattern throughout his head and neck, upper trunk, hands, forearms and thighs. The papules are arranged in a strikingly linear array. The surrounding skin is shiny and indurated and the glabella has deep longitudinal furrowing. Deep furrowing also is present on the trunk and extremities. A biopsy showed: mucin in the upper and mid-reticular dermis, increase collagen deposition, and a marked proliferation of irregularly arranged fibroblasts. Which of the following is the most likely diagnosis?
A. Scleroderma
B. Scleredema
C. Pachydermoperiostosis
D. Scleromyxedema
E. Nephrogenic systemic fibrosis
Correct choice:D. Scleromyxedema
Explanation: In scleromyxedema, numerous 2–3 mm firm waxy closely aligned papules develop in a relatively widespread symmetrical pattern. The most common sites of involvement are the head and neck region, upper trunk, hands, forearms and thighs. Papules are often arranged in a strikingly linear array. The surrounding skin is shiny and indurated, i.e. sclerodermoid in appearance, and the glabella is typically involved with deep longitudinal furrowing. Severe involvement of the face can result in a leonine facies. Deep furrowing can also occur on the trunk and extremities and is referred as the “Shar-Pei sign.”
Scleromyxedema is characterized by a triad of microscopic features:
- a diffuse deposit of mucin in the upper and mid reticular dermis
- an increase in collagen deposition
- a marked proliferation of irregularly arranged fibroblasts
1 -The primary differential diagnosis for scleromyxedema is systemic sclerosis (scleroderma) and scleredema. The presence of papules, especially in linear arrays, is a very helpful clinical sign in distinguishing scleromyxedema
2- Scleredema is a symmetrical diffuse induration of the upper part of the body due to a thickened dermis and deposition of mucin.
3 - Pachydermoperiostosis (primary hypertrophic osteoarthropathy) is associated with facial involvement, thickening of the skin on the hands and feet, and clubbing of the digits.
5 - Nephrogenic systemic fibrosis, which develops in individuals with renal impairment exposed to gadolinium-containing contrast media, may show mucin in biopsy specimens, but patients lack both facial involvement (commonly seen in scleromyxedema) and paraproteinemia.
- A too superficial biopsy of this neoplasm could be misdiagnosed as which lesion?
A. Desmplastic trichoepithelioma
B. Cylindroma
C. Spiradenoma
D. Syringoma
E. Chondroid syringoma
Correct choice: D. Syringoma
Explanation: Superficial biopsies of microcystic adnexal carcinoma are sometimes misdiagnosed as syringomas. Microcystic adnexal carcinomas demonstrate ductal structures and cords in a fibrous stroma. They extend deep into the dermis and even subcutis.
- Weibel-Palade bodies are seen in:
A. Endothelial cells
B. Spitz Nevi
C. Cells infected with MCV
D. Plasmacytoid Cells
E. Malakoplakia
Correct choice: A. Endothelial cells
Explanation: Weibel-Palade bodies are seen in endothelial cells and are therefore found in vascular lesions. Kamino bodies are found in Spitz nevi. Henderson Patterson bodies are seen in molluscum. Dutcher bodies are intranuclear inclusions seen in plasmacytoid cells. Michaelis Gutmann bodies are partially digested bacteria seen in malakoplakia.
At the ultrastructural level, vascular endothelial cells are characterized by tight junctions between neighboring cells and by specialized organelles, the rod-shaped Weibel–Palade bodies, that serve as storage organelles for the coagulation factor von Willebrand factor, also known as factor VIII- related antigen. Weibel–Palade bodies also contain P-selectin, angiopoietin-2, and endothelin-1. Activation of endothelial cells by proinflammatory cytokines or pro-angiogenic factors readily leads to translocation of these storage organelles to the cell membrane, with consecutive enhanced membrane expression of P-selectin and release of von Willebrand factor. Other characteristic ultrastructural features include caveolae (minute invaginations of the membrane surface), pinocytotic vesicles, and the formation of vesiculo-vacuolar organelles. Circulating macromolecules cross the endothelium through interendothelial cell gaps and transendothelial cell pores, some of which arise from VVOs. Endothelial cell fenestrations, areas with direct apposition of the endothelial cell membranes without intervening cytoplasm, are rarely seen in normal skin except in angiogenic perifollicular blood vessels during the growth phase of the hair follicle. However, fenestrated endothelial cells are frequently seen in skin diseases with pronounced angiogenesis and vascular hyperpermeability, including psoriasis.
- In this disorder which typically occurs on the head and neck, the cells would demonstrate which staining pattern?
A. CD1a + and S100 +
B. CD1a- and S100 -
C. CD1a+ and S100-
D. CD1a- and S100+
E. CD68-
Correct choice: B. CD1a- and S100 -
Explanation: Benign cephalic histiocytosis is a benign eruption that typically occurs on the face of children. It is a non-Langerhans cell histiocytosis; hence, it is CD1a and S100 negative but is CD68 positive.
- A pregnant 33-year-old female presents with the shown painful lesions that appeared abruptly one week ago. She additionally has been febrile to 38.3C with malaise and headaches. What do you expect to find on biopsy of a representative lesion?
A. Perivascular neutrophils with fibrinoid necrosis and RBC extravasation
B. Apoptotic individual keratinocytes with intracellular spongiosis
C. Dense peri-eccrine gland neutrophilic infiltrate
D. Diffuse infiltration of malignant leukocytes in the dermis
E. Superficial dermal edema with dense neutrophilic infiltrate
Correct choice: E. Superficial dermal edema with dense neutrophilic infiltrate
Explanation: The clinical presentation most likely represents Sweet syndrome (acute febrile neutrophilic dermatosis). Classical Sweet syndrome is frequently associated with recent infections, IBD and pregnancy. Diagnosis is made with 2 major and 2 minor criteria.
Major criteria: 1. Abrupt onset of painful erythematous plaques 2. Histopathological evidence of a dense neutrophilic infiltrate without evidence of leukocytoclastic vasculitis
Minor criteria: 1. Fever 2. Association with malignancy, inflammatory disease, pregnancy or recent URI, GI infection, vaccination 3. Excellent response to systemic steroids 4. Abnormal lab values (ESR, CRP, leukocytosis, >70% neutrophils)
Option A represents leukocytoclastic vasculitis. Option B represents erythema multiforme. Option C is the pathology for neutrophilic eccrine hidradenitis. Option D represents leukemia cutis.
- Histopathologically, a swiss cheese type appearance is characteristic to which of the following?
A. Silica
B. Tattoos
C. Liquid silicone
D. Sea urchin spines
E. Zirconium
Correct choice: C. Liquid silicone
Explanation: Paraffinoma and silicone granuloma both have a swiss cheese type appearance in the dermis to subcutaneous fat. The remaining options typically appear sarcoidal.
- What is the most likely diagnosis?
A. Verrucous carcinoma
B. Keratoacanthoma
C. Basal cell carcinoma
D. bowen’s disease
E. pilomatrichoma
Correct choice: A. Verrucous carcinoma
Explanation: Verrucous carcinoma is a large nedophytic condylomatous lesion. It is giant, well differentiated and has a pushing margin.
- Multiple pilomatricomas are seen in all of the following syndromes EXCEPT:
A. Gardner syndrome
B. Cowden syndrome
C. Turner syndrome
D. Rubinstein-Taybi syndrome
E. Myotonic dystrophy
Correct choice: B. Cowden syndrome
Explanation: Multiple pilomatricomas are seen in Rubinstein-Taybi, Gardner’s (cyst-like pilomatricomas), myotonic dystrophy, Turner’s, sarcoidosis, sternal cleft and coagulation defects. Cowden syndrome does not commonly demonstrate pilomatricomas.
- The mutation that most likely resulted in this lesion is which of the following?
A. PTCH
B. CDKN2A
C. VEGF
D. P53
E. RET
Correct choice: D. P53
Explanation: P53 is the most common mutation in squamous cell carcinoma. This SCC is located on the lip. PTCH is mutated in BCCs and CDKN2A is mutated in familial melanomas.
- A healthy, full-term, 24-hour-old newborn girl develops a rash consisting of blotchy, erythematous papules on the face, trunk and extremities. Which of the following would most likely be seen on biopsy?
A. Perifollicular subcorneal pustules with eosinophils
B. Subcorneal pustules with neutrophils
C. Spongiosis and hyphae in the stratum corneum
D. Acantholysis and multinucleated cells
E. Abrupt ballooning of the upper one-third of the epidermis
Correct choice: A. Perifollicular subcorneal pustules with eosinophils
Explanation: This scenario most likely describeds erythema toxicum neonatorum, which would show perrifollicular subcorneal pustules with eosinophils on biopsy. Subcorneal pustules with neutrophils is consistent with transient neonatal pustular melanosis, which typically presents at birth. Spongiosis and hyphae in the stratum corneum can be seen with dermatophyte infection. Acantholysis and multinucleated cells can be seen with viral infection such as HSV. Abrupt ballooning of the upper one-third of the epidermis is consistent with nutritional deficiency.
- All are sebaceous glands except:
A. Tyson
B. Moll
C. Montgomery tubercle
D. Fordyce
E. Meibomian
Correct choice: B. Moll
Explanation: Moll’s glands are modified apocrine glands located on the eyelid. Sebaceous glands in certain locations have an associated name (Tyson’s on the penis, Montgomery tubercle on the areola, Meibomian on the eyelid, and Fordyce on the vermilion/oral mucosa).
- What stain will more clearly reveal the organisms in the biopsy shown?
A. PAS
B. S100
C. CD68
D. CD3
E. Oil red O
Correct choice: A. PAS
Explanation: The histology shows an infiltrate of fungal hyphae. They will highlight with PAS and a silver stain. This is aspergillus.
- Eosinophilia-Myalgia syndrome is caused by:
A. Norwegian salt-petter
B. Unadultered Spanish grapeseed oil
C. Pb intoxication
D. L-Tryptophan
E. Excessive anaerobic exercise
Correct choice: D. L-Tryptophan
Explanation: The eosinophilia myalgia syndrome is characterized by marked peripheral eosinophilia with a clinical spectrum of signs and symptoms, including generalized myalgias, pneumonitis, myocarditis, neuropathy, encephalopathy and fibrosis. Many patients progress to a clinical picture clinically indistinguishable from eosinophilic fasciitis. The disease is caused by the ingestion of certain lots of L-tryptophan.
Eosinophilia-myalgia syndrome (EMS) was first identified in 1989, when approximately 1500 patients developed subacute onset of myalgias and peripheral eosinophilia.They then went on to have chronic muscle, fascia, nerve, and skin involvement. The Centers for Disease Control and Prevention (CDC) proposed a surveillance case definition that included the following:
* Incapacitating myalgias
* Peripheral eosinophil count greater than 1000/µL
* No evidence of infection (ie, trichinosis) or neoplasm
Studies quickly linked EMS to dietary supplements which contained L-tryptophan, a supplement commonly used by patients with fibromyalgia syndrome (FMS), which was made using genetically engineered bacteria. Specifically, the analysis found an impurity identified as 1’1’- ethylidenebis[tryptophan] (EBT). This supplement was quickly removed from the market resulting in swift resolution of the EMS epidemic, but unfortunately there were over 30 deaths in just 6 months. Since then, other causes of EMS have been implicated. Six other impurities in L- tryptophan, including 3-(phenylamino) alanine (PAA), shares similar properties with 3-(N- phenylamino)-1,2-propanediol (the chemical found in rapeseed oil and implicated in the 1981 Spanish toxic oil syndrome epidemic, have been associated with EMS.
- Which class of medication is associated with the development of this neoplasm?
A. ACE inhibitors
B. Beta blockers
C. Protease inhibitors
D. TNF alpha inhibitors
E. Antifungals
Correct choice: C. Protease inhibitors
Explanation: Protease inhibitors have been associated with a lipodystrophy syndrome in some patients with HIV, including the development of angiolipomas. Histologic features of an angiolipoma include normal subcutaneous fat with the presence of thrombosed blood vessels.
- This is a DIF image of a lesion of lichen planus (Anti-IgM ab). What does the image show?
A. Granular deposits at the dermal-epidermal junction
B. Shaggy deposits along the dermal-epidermal junction
C. Colloid/cytoid bodies
D. Caterpillar bodies
Correct choice: C. Colloid/cytoid bodies Explanation: Colloid/cytoid bodies
- Which of the following is true of Rosai-Dorfman disease?
A. S-100 negative, CD1a positive, not characterized by emperipolesis
B. S-100 positive, CD1a positive, not characterized by emperipolesis
C. S-100 positive, CD1a negative, characterized by emperipolesis
D. S-100 positive, CD1a positive, characterized by emperipolesis
E. S-100 negative, CD1a negative, characterized by emperipolesis
Correct choice: C. S-100 positive, CD1a negative, characterized by emperipolesis
Explanation: Rosai-Dofrman disease (also known as sinus histiocytosis with massive lymphadenopathy) is characterized by large “fluffy” histiocytes that are S-100 positive but CD1a negative, and is characterized by multinucleated giant cells, plasma cells, aggregates of lymphocytes, and emperipolesis. There is debate as to whether the condition is related to herpes type 6.
- This lesion is often found in which anatomic location?
A. Skin folds
B. Acral sites
C. Scalp
D. Mucosa
E. Trunk
Correct choice: A. Skin folds
Explanation: This image demonstrates an infarcted skin tag. Skin tags are common in skin folds.
- Which of the following pathologic markers is most likely to be negative in a case of melanoma?
A. HMB45
B. MelanA
C. Keratin
D. S100
E. Vimentin
Correct choice: C. Keratin
Explanation: Melanomas uniformly stain negative for keratin, which helps differentiate between Paget’s/Extramammary Paget’s Disease (keratin stain is positive) and pagetoid melanoma.
The remaining listed answer choices will be positive in melanoma. The only exception is cases of desmoplastic/spindle cell melanoma, wherein HMB45 is negative.
- The predominant location of the cleft in transient neonatal pustular melanosis is:
A. Dermal
B. Basement membrane zone
C. Basal keratinocytes
D. Suprabasal
E. Subcorneal/granular
Correct choice: E. Subcorneal/granular
Explanation: Transient neonatal pustular melanosis is an idiopathic pustular eruption of newborns, mostly on the chest, that heals with hyperpigmentation. It is most common on pigmented individuals. Histologically it presents as subcorneal pustules with eosinophils and neutrophils.
- Which of the following have been found to develop within a nevus sebaceous?
A. Angiosarcoma
B. Merkel cell carcinoma
C. Syringocystadenoma Papilliferum
D. Syringoma
E. Hidradenoma Papilliferum
Correct choice: C. Syringocystadenoma Papilliferum
Explanation: Historically, the most common benign tumor to develop within a nevus sebaceous was syringocystadenoma papilliferum, although the most recent literature indicates that trichoblastoma arises more commonly. The most common malignant tumor to arise is a basal cell carcinoma. Cutaneous leiomyosarcoma, verruca, sebaceoma, and squamous cell carcinoma have also been reported to be found within a nevus sebaceous. There are no reports of angiosarcoma, merkel cell carcinoma, syringoma, or hidradenoma papilliferum arising within a nevus sebaceous.
- What is the best diagnosis?
A. Cholesterol emboli
B. Masson’s Tumor
C. Calciphylaxis
D. Leukocytoclastic vasculitis
E. Processing Artifact
Correct choice: A. Cholesterol emboli
Explanation: Cholesterol Emboli: Typically occurs after a vascular procedure but can occur spontaneously. Usually presents as livedo reticularis of distal lower extremities, associated with eosinophilia and acute renal failure. Often need multiple deeper levels on sectioning a punch biopsy to see the characteristic cholesterol clefts and fibrin thrombi in the lower dermis or subcutis. A high index of suspicion is required especially in a patient with known atherosclerosis who has developed the typical skin changes, kidney failure, abdominal pain or diarrhea, following a vascular procedure.
Definitive diagnosis is made from a skin biopsy or a biopsy of other involved tissue. The histology of cholesterol emboli should show diagnostic cholesterol crystals or clefts within the blood vessel wall, along with thrombi (blood clots). The clefts are spaces left by the crystals that have been washed out by the tissue fixation.
Blood tests show an eosinophilia in up to 80% of affected patients. Other changes that may be seen include: Raised white cell count and/or platelet count, Microscopic blood in the urine or stool, Elevated erythrocyte sedimentation rate (ESR), Deranged kidney function tests, Raised amylase levels, Decreased serum complement.
- Which syndrome is associated with this lesion?
A. Proteus
B. Sturge- Weber
C. Parkes Weber
D. Klippel-Trenaunay
E. Cutis marmorata telangiectatica congenital
Correct choice: C. Parkes Weber
Explanation: Parkes Weber syndrome is associated with arteriovenous malformations. All other listed syndromes are associated with capillary malformations.
- On histologic examination of this adenocarcinoma of the perineal area, which of the following stains would NOT be positive?
A. PAS
B. Mucicarmine
C. CEA
D. EMA
E. HMB45
Correct choice: E. HMB45
Explanation: Extramammary Paget’s disease (EMPD) is a cutaneous adenocarcinoma of glandular differentiation. Approximately 25% of EMPD cases are associated with underlying neoplasms. They stain negative for HMB45, which is a melanocytic marker. Histologically, the Paget cells stain positively with PAS, mucicarmine, CEA, EMA, LMW keratin.
- Which of the following is correct regarding using histologic stains to differentiate between primary extramammary Paget’s disease and pagetoid metastasis to the skin from underlying colon cancer?
A. Extramammary Paget’s disease is carcinoembryonic antigen (CEA) negative.
B. Extramammary Paget’s disease is HMB45-positive
C. Extramammary Paget’s disease is gross cystic disease fluid protein-15 positive.
D. Pagetoid metastasis to the skin from underlying colon cancer is CK7-positive
E. Pagetoid metastasis to the skin from underlying colon cancer is CK20-negative
Correct choice: C. Extramammary Paget’s disease is gross cystic disease fluid protein-15 positive.
Explanation: Primary extramammary Paget’s disease is gross cystic disease fluid protein-15 positive, whereas pagetoid metastasis to the skin from underlying colon cancer is typically gross cystic disease fluid protein-15 negative. Primary extramammary Paget’s disease also is CK7- positive and CK20-negative, whereas pagetoid metastasis to the skin from underlying colon cancer is CK7-negative and CK20-positive. Both conditions typically show positive staining with CEA and EMA, and negative staining with HMB-45 (which would be positive in Pagetoid melanoma).
- What is the foreign material seen in this biopsy?
A. Gel foam
B. Splinter
C. Sculptra
D. Hyaluronic acid
E. Silicone
Correct choice: A. Gel foam
Explanation: This is gelfoam on histology, it typically has the deep purple color, is amorphous and has jagged edges.
- Which of the following is an immunhistochemical marker for Merkel Cell Carcinoma?:
A. S-100
B. Vimentin
C. HMB-45
D. Neuron specific enolase
E. TTF-1
Correct choice: D. Neuron specific enolase
Explanation: Neuron specific enolase stains merkel cells. Vimentin stains melanocytic lesions, sarcomas and lymphomas. S-100 and HMB-45 stains melanocytic lesions, such as melanoma. TTF-1 is positive in small cell carcinoma of the lung.
- Goblet cells are seen in:
A. Cutaneous ciliated cyst
B. Endometriosis
C. Dermoid cyst
D. Bronchogenic cyst
E. Steatocystoma
Correct choice: D. Bronchogenic cyst
Explanation: Bronchogenic cysts have a pseudostratified cuboidal or columnar lining that is ciliated; goblet cells are found in the lining as well.
- The type of necrosis shown in the center of this lesion is which of the following?
A. Fat necrosis
B. Liquefactive necrosis
C. Fibrinoid necrosis
D. Caseous necrosis
E. Coagulative necrosis
Correct choice: D. Caseous necrosis
Explanation: Granulomas with central caseous necrosis is a classic histopathologic finding for LMDF.
- These lesions are common in the genodermatosis caused by which gene mutation?
A. PTEN
B. BRAF
C. NFKB
D. CYLD
E. ABCC6
Correct choice: D. CYLD
Explanation: Brooke-Spiegler syndrome is caused by a mutation in the CYLD gene. It is characterized by the presence of spiradenomas, cylindromas, and trichoepitheliomas.
- Which of the following statements about the direct immunofluorescence pattern in lichen planus is correct?
A. The DIF is negative in the majority of cases
B. Deposition of IgG is within cytoid bodies in the superficial dermis
C. Shaggy deposition of fibrin occurs at the DEJ
D. Deposition of fibrinogen is within cytoid bodies in the deep dermis
E. There is prominent deposition of IgM within the spinous layer of the epidermis
Correct choice: C. Shaggy deposition of fibrin occurs at the DEJ
Explanation: Shaggy fibrin deposition at the DEJ, which is the single best indicator in the diagnosis of LP, was found in 56% of cases according to one study evaluating the DIF fndings in patients with LP. The DIF is positive in the majority of cases (75% according to one study). Deposition of IgM and fibrinogen is within cytoid bodies in the superficial dermis. There is no deposition of IgM within the spinous layer of the epidermis.
- You examine a biopsy that is square on low power. The clinical history reports an IgG paraproteinemia and the presence of a “doughnut sign”. Which of the following conditions would you think of without looking on higher power?
A. Scleromyxedema
B. Scleroderma
C. Scleredema
D. Localized Morphea
E. Pretibial myxedema
Correct choice: A. Scleromyxedema
Explanation: The doughnut sign is seen on proximal interphalangeal joints where a central depression surrounded by an elevated rim can be seen. This is a feature of the skin thickening seen in Scleromyxedema. The other options will have a square appearance on low power microscopic examination and scleredema can have an IgG paraprotein. Other microscopic findings in scleromyxedema include incrased fibroblasts with fibrosis/increased collagen and thickening of the dermis. Mucin may be scant or absent. This biopsy is more cellular than pretibial myxedema. The other options will have a square appearance on low power microscopic examination and scleredema can have an IgG paraprotein. Other microscopic findings in scleromyxedema include incrased fibroblasts with fibrosis/increased collagen and thickening of the dermis. Mucin may be scant or absent. This biopsy is more cellular than pretibial myxedema.
- When attempting to identify Langerhans cells in a specimen, which of the following markers is most helpful?
A. CD1a
B. CD4
C. CD7
D. CD8
E. CD20
Correct choice: A. CD1a
Explanation: CD1a is a surface antigen specific for epidermal Langerhans cells. It is not expressed on other epidermal structures. Another specific marker of Langerhans cells is CD207 (aka langerin). The other characteristic ultrastructural feature of Langerhans cells is the Birbeck granule, which is shaped like a tennis racket. CD4 is found on T-helper cells and occasionally on Langerhans cells. CD7 is a T-cell marker that is often lost in cutaneous T-cell lymphoma. CD8 is found on cytotoxic T-cells. CD20 is a B-cell marker.
- Scalp biopsy of a 14-year-old female with suspected alopecia areata would likely reveal inflammation around which portion of the hair follicle:
A. Dermal papilla
B. Hair bulb
C. Inner root sheath
D. Isthmus
E. Infundibulum
Correct choice: B. Hair bulb
Explanation: On biopsy, alopecia areata exhibits a peribulbar lymphocytic “swarm of bees.”
Discoid lupus typically exhibits inflammation surrounding the isthmus, along with a perivascular dermatitis and vacuolar interface changes. Lichen planopilaris exhibits inflammation most densely concentrated about the infindibulum.
- The promontory sign is seen in:
A. Tufted angioma
B. Glomeruloid hemangioma
C. Spindle cell hemangioendothelioma
D. Acroangiodermatitis of Mali
E. Kaposi’s sarcoma
Correct choice: E. Kaposi’s sarcoma
Explanation: The promontory sign refers to the formation of new vessels around existing vessels and adnexal structures. This is typically seen in Kaposi’s sarcoma. However, it is not pathognomonic, because it has also been described in angiosarcoma and in benign vascular tumors.
- What is this lesion called when it is located in the salivary gland?
A. Chondroid syringoma
B. Pleomorphic adenoma
C. Pororma
D. Basal cell carcinoma
E. Spiradenoma
Correct choice: B. Pleomorphic adenoma
Explanation: This is a chondroid syringoma or mixed tumor of the skin. When a chondroid syringoma is in the salivary gland it is called a pleomorphic adenoma. They look almost identical histologically, and are named differently due to their location.
- A 14-year-old boy presents with brownish, verrucous, scaly skin with prominent flexural involvement. A biopsy shows the findings above (pictured). Which of the following is the most likely diagnosis?
A. X-linked ichthyosis
B. Bullous congenital ichthyosiform erythroderma
C. Lamellar ichthyosis
D. Erythrokeratoderma variabilis
E. Sjogren-Larsson syndrome
Correct choice: B. Bullous congenital ichthyosiform erythroderma
Explanation: Epidermolytic hyperkeratosis is also known as bullous congenital ichthyosiform erythroderma and is autosomal dominant. It is characterized by brownish, verrucous, scaly skin with a “corrugated cardboard” appearance to the skin, prominent flexural involvement, and vesicles and bullae that may occur early in life. It is caused by a defect in keratin 1 and keratin 10 (suprabasal keratins). Histologically, it demonstrates compact orthokeratosis and acanthosis, hypergranulosis, and a distinct type of degeneration of keratinocytes known as “epidermolytic hyperkeratosis” which appears as though the superficial epidermis is degenerated or “blown out by a shotgun.” Sometimes there are intraepidermal blisters in the degenerated areas early in infancy.
1 – X-linked ichthyosis is a brownish scaly eruption that begins in early childhood in males. It is associated with steroid sulfatase deficiency (STS gene). It does not have the same characteristic histologic features as epidermolytic hyperkeratosis. 3 – Lamellar ichthyosis is an autosomal recessive disorder characterized by severe thick plates of scale that resemble reptile scales with an onset usually at birth. It may present as collodion baby and can involve the flexures, palms and soles. It is associated with a mutation in keratinocyte transglutaminase. It does not have the same characteristic histologic features as epidermolytic hyperkeratosis. 4 – Erythrokeratoderma variabilis is a rare, autosomal dominant mutation in the genes for gap junction proteins GJB3 and GJB4, and is characterized by onset within 1 year of age, polycyclic to annular migrating red scaly plaques and often palmoplantar keratoderma. It does not have the same characteristic histologic features as epidermolytic hyperkeratosis. 5 – Sjogren-Larsson syndrome is a rare autosomal recessive condition caused by a mutation in ALDH3A2 gene for fatty aldehyde dehydrogenase. It is characterized by seizures, retinitis pigmentosa, lamellar ichthyosis, mental retardation and spastic paresis. It does not have the same characteristic histologic features as epidermolytic hyperkeratosis.
- What is the diagnosis?
A. silicone
B. monsels
C. aluminum chloride
D. gel foam
E. tattoo
Correct choice: E. tattoo
Explanation: Tattoo is a pigment deposited deep in the dermis, and is whatever color the tatto itself is. Gel foam is purple; silicone is a group of small bubbles; and monsels is more of a brown color and is localized.
- A 35-year-old man develops indurated, mildly erythematous plaques involving the face and upper back. Biopsy reveals a perivascular and periadnexal lymphocytic infiltrate with no overlying epidermal changes. Which histopathologic stain could be used to support a diagnosis of tumid lupus?
A. Fontana-Masson
B. Giemsa
C. von Kossa
D. Colloidal iron
E. Osmium tetroxide
Correct choice: D. Colloidal iron
Explanation: Tumid lupus is characterized by increased mucin, and thus a mucin stain such as colloidal iron may be used to accentuate these findings. Other disorders that may present with a superficial and deep perivascular lymphocytic infiltrate without associated increased dermal mucin include polymorphous light eruption, pernio, syphilis, and reactive lymphocytic infiltrate of Jessner, among others. Giemsa stains the granules in mast cells.
- A patient presents with a brown patch that has darker macules within it and this pathology. What is the best diagnosis?
A. Nevus spilus
B. linchen nitidus
C. lichen striatus
D. nevus comedonicus
E. agminated nevus
Correct choice: A. Nevus spilus
Explanation: Nevus spilus is a tan macule/patch with darker smaller maclues scattered within it. On pathology, you see an increased number of melanocytes in a lentigenous pattern along the DEJ with increased nests in focal areas. In an agminanated nevus there are groups of brown macules on normal skin. There is no background brown macule differentiating it from nevus spilus.
- Which of the following stains would you expect to be positive in a normal eccrine unit?
A. S-100
B. Prussian blue
C. Giemsa
D. Verhoeff von Gieson
E. Steiner
Correct choice A. S-100
Explanation: Eccrine glands stain S-100 and CEA positive. The remaining stains would not be expected to stain normal eccrine sweat glands. Prussian blue (Perl’s) is an iron stain which stains iron or hemosiderin bright blue. Giemsa stains mast cell granules purple (heparin in the granules) and can also be useful in staining in Leishmaniasis. Verhoeff von Gieson is a stain for elastic tissue
that stains blue-black. Steiner stain is a silver stin for spirochetes similar to a Warthin Starry or Dieterle stain.
- Which of the following is characteristic of lichen planus histopathologically?
A. Wedge-shaped parakeratosis
B. Irregular acanthosis
C. Absent interface changes
D. Parakeratosis
E. Absent granular layer
Correct choice:. Irregular acanthosis
Explanation: Histopathology of lichen planus: Acanthosis with wedge-shaped hypergranulosis, irregular (sawtooth acanthosis), hyperkeratosis without significant parakeratosis, and basal vacuolization (interface changes). In most cases, lichen planus is diagnosed by observing its clinical features. A biopsy is often recommended to confirm or make the diagnosis and to look for cancer. The histopathological signs are of a lichenoid tissue reaction affecting the epidermis.
Typical features include:
- Irregularly thickened epidermis
- Degenerative skin cells
- Liquefaction degeneration of the basal layer of the epidermis
- Band of inflammatory cells just beneath the epidermis
- Melanin (pigment) beneath the epidermis
- Direct immunofluorescent staining may reveal deposits of immunoglobulins at the base of the epidermis.
- This patient presented with a papulosquamous eruption involving his palms, soles and trunk. He notes that three weeks ago he had a small lesion on his penis that healed within a week. What is your most likely diagnosis?
a. Syphilis
b. haemophilus ducryi
c. LGV
d. HSV
e. psoriasis
Correct choice: A. Syphilis
Explanation: Secondary syphilis presents with a papulosquamous eruption that includes the palms and soles. They may or may not remember the penile chancre as it is painless. Both haemophilus ducryi and HSV are painful.
- A biopsy was performed from the scalp of an elderly man what is the most likely diagnosis?
A. Metastatic renal cell carcinoma
B. Angiosarcoma
C. Carcinoid
D. Sebaceous Carcinoma
E. Clear cell hidradenoma
Correct choice A. Metastatic renal cell carcinoma
Explanation: Clear Cell Renal Carcinoma: Metastatic lesions are commonly located on the scalp. The tumor itself is composed of cells with clear to slightly granular cytoplasm secondary to increased glycogen and lipid. The tumors typically forms abortive tubes/ducts, cords or sheets of cells. Immunohistochemical stains are + for EMA and CD10. Typically the tumor is very vascular with scant stroma associated with extravasated RBC and hemosiderin. The differential diagnosis includes clear cell hidroadenoma. This latter tumor is usually composed of a mixture of components; solid areas composed of small poroid cells often with duct formation admixed with clear cells and squamoid cells. The tumor can be solid or cystic or a combination of the two. The large cystic spaces typically contain sialomucin. The stroma is delicate fibrovascular. The tumor is + CAM 5.2, CEA, EMA, with glycogen and no lipid in the clear cells.
Skin metastases of renal cell carcinoma present as nodular, rapidly growing, round or oval- shaped lesions, which can be of various colors ranging from normal skin color to a red-purple color. Clinical presentation may be confused with hemangioma, basal cell carcinoma or pyogenic granuloma. There was a similar appearance of hemangioma in our case. In histopathological examination, atypical nucleated cells are expected to be seen in clear cell type. The nodular mass is surrounded by the atrophic epidermis, and moderate lymphocytic infiltration can be observed. Lesions should be considered xanthoma, xanthelasma, hidradenoma in the differential diagnosis. The immunohistochemical examination provides a microscopic differential diagnosis. Epithelioid membrane antigen, carcinoembryonic antigen, CD-10, renal cell carcinoma marker are markers used to identify skin metastases of renal cell carcinoma.
- Lipomembranous change is seen in:
A. Hibernoma
B. Cystic sebaceous adenoma
C. Sebaceous carcinoma
D. Mucocele
E. Sclerosing panniculitis
Correct choice: E. Sclerosing panniculitis
Explanation: Lipomembranous change is a non-specific histologic pattern that is most commonly seen in lipodermatosclerosis, which is also known as sclerosing panniculitis; this condition may be secondary to venous stasis.
- What material is present in the dermis in this image?
A. Hyaluronic acid filler
B. Cartilage
C. Bone
D. Calcium
E. Urate
Correct choice: D. Calcium
Explanation: This image demonstrates calcinosis in the dermis.
- Which of the following does NOT stain for mucopolysaccharides (mucin)?
A. Periodic-acid Schiff (PAS)
B. Trichome
C. Alcian blue
D. Colloidal iron
E. Mucicarmine
Correct choice: B. Trichome
Explanation: Trichome does not stain acid mucopolysaccharides. Trichome stains collagen blue or green and muscle red depending on reagents used. PAS stains mucopolysaccharides red, alcian blue stains mucopolysaccharides blue, colloidal iron stains mucin blue and mucicarmine stains mucin red. PAS stains mucopolysaccharides red, alcian blue stains mucopolysaccharides blue, colloidal iron stains mucin blue and mucicarmine stains mucin red.
- The globi in this Fite-Faraco stain represent:
A. clumping of mycobacteria
B. degradation of mycobacteria
C. isolated bacilli
D. fragmentation of organisms
E. granular mycobacteria
Correct choice: A. clumping of mycobacteria
Explanation: In lepromatous leprosy, acid-fast bacilli are seen with the Fite stain, sometimes in clumps called globi.
- Merkel cell carcinomas are seen in older patients and present with a skin-colored to erythematous or violaceous papule in a sun exposed distribution. The cytokeratin 20 is positive in:
A. 90% of cases
B. 70% of cases
C. 50% of cases
D. 30% of cases
E. 20% of cases
Correct choice: A. 90% of cases
Explanation: Patient that are diagnosed with Merkel cell carcinoma will test positive for cytokeratin 20 in 90% of the time with perinuclear dot pattern. It also tests positive in CAM5.2, NSE +, chromogranin, and synaptophysin+. It is also thyroidd transcription factor-1 negative and s-100 negative.
- The cytoplasmic granules seen in granular cell tumor are:
A. Phagolysosomes
B. Ribosomes
C. Mitochondria
D. Intermediate filaments
E. Vacuoles
Correct choice: A. Phagolysosomes
Explanation: The granules in granular cell tumor are phagolysosomes.
The granularity of the granular cell layer in epidermodysplasia verruciformis may be secondary to increased ribosomes. Mitochondria fill the cells in hibernoma.
- What would this lesion stain positively with?
A. Von Kossa
B. VVG
C. Oil red O
D. Thioflavin T
E. Desmin
Correct choice: D. Thioflavin T
Explanation: This is nodular amyloid which stains with thioflavin T and crystal violet. Oil red O stains fat, elastin is stained by VVG, Von Kossa stains calcium and desmin stains muscle.
- Which of the following stains would be helpful in the diagnosis of cryptococcosis?
A. Colloidal iron
B. Oil red O
C. Mucicarmine
D. Giemsa
E. Verhoeff von Gieson
Correct choice: C. Mucicarmine
Explanation: The yeast cytoplasm of Cryptococcus neoformans stains with PAS and methenamine silver, while the the capsule stains with Alcian blue and mucicarmine.Colloidal iron stains mucin; Oil red O stains fat; Giemsa stains mast cells and leishmaniasis; Verhoeff von Gieson stains elastic tissue.
- One month after starting carbamazepine for new onset epilepsy, your patient develops an extensive eruption with peripheral eosinophilia and associated liver dysfunction. Which histologic finding would be most suggestive of the rash based on the clinical history?
A. Perivascular lymphocytic infiltrate with mild interface changes
B. Atypical basaloid cells in the papillary dermis
C. Irregular acanthosis with saw-toothed rete ridges
D. Neutrophils in the stratum corneum
E. Multinucleated giant cells
Correct choice: A. Perivascular lymphocytic infiltrate with mild interface changes
Explanation: Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) - also termed Drug-Induced Hypersensivity Syndrome (DIHS) is a syndrome of systemic illness related to a medication. Anti-epileptic medications and a longer duration of use prior to reaction (here 4 weeks) is typical. The histopathology is variable but most often shows a superficial perivascular lymphocytic infiltrate with mild interface changes.
The other options are not seen in this kind of drug reaction;Atypical basaloid cells in the papillary dermis are more concerning for a malignancy. Irregular acanthosis and saw-toothed rete ridges is seen in lichen planus. Neutrophils in the stratum corneum may be seen in AGEP. Multinucleated giant cells are seen in other scenarios such as histocytic reactions.
- This lesion (choose CORRECT answer)
A. Is a hypertrophic scar
B. Is a leiomyoma
C. Is a Becker’s nevus
D. Is a dermatomyofibroma
Correct choice: D. Is a dermatomyofibroma
- Which type is most common in children?
A. Type 1
B. Type 4
C. Type 3
D. Type 2
E. Type 5
Correct choice: B. Type 4
Explanation: In PRP, type 4, circumscribed juvenile is the most common form in kids. Type 1 is classic adult. Type 2 is atyical, chronic adult. Type 3 is classic juvenile, type 5 is atypical juvenile.
- Psoriasiform dermatitis with irregular hyperkeratosis and alternating vertical and horizontal ortho- and parakeratosis is distinctive of this disorder:
A. psoriasis vulgaris
B. guttate psoriasis
C. parapsoriasis
D. pityriasis rubra pilaris
E. cutaneous T-cell lymphoma
Correct choice: D. pityriasis rubra pilaris
Explanation: Psoriasiform dermatitis with irregular hyperkeratosis and alternating vertical & horizontal ortho- and parakeratosis (“checkerboard pattern”) is distinctive of pityriasis rubra pilaris. The hair follicles are dilated and filled with a keratinous plug, while the “shoulder” of stratum corneum surrounding the follicular opening frequently shows parakeratosis.
- The pathology of this lesion demonstrates reticulate strands of the epidermis with clefting between the strands and the stroma. What is the diagnosis?
A. Eccrine syringofibroadenoma
B. Fibroepithelioma of Pinkus
C. Squamous cell carcinoma
D. Reticulate seborrheic keratosis
E. Tumor of the follicular infundibulum
Correct choice: B. Fibroepithelioma of Pinkus
Explanation: This is a fibroepithelioma of Pinkus, which is a BCC. Therefore, it has clefting between the reticulate strands and the stroma.
- Which disease frequently demonstrates this finding?
A. Morphea
B. Atopic dermatitis
C. Langerhans cell histiocytosis
D. Rosacea
E. Dermatomyositis
Correct choice: E. Dermatomyositis
Explanation: Calcinosis cutis is a common occurrence in dermatomyositis, especially the juvenile form of the disease.
- This condition frequently occurs on which part of the body?
A. Abdomen
B. Forearms
C. Scalp
D. Neck
E. Finger
Correct choice: B. Forearms
Explanation: Actinic purpura typically occurs in older individuals on sun-damaged, traumatized skin such as the forearms.
- This is a culture of a fungus. What is it?
A. Rhizopus
B. Phaeohyphomycosis
C. Aspergillosis
D. Mucor
E. Absidia
Correct choice: A. Rhizopus
Explanation: Mucormycosis: Rhizopus the roots are directly under sporangia. This is # 1 cause of localized and systemic disease due to mucormycosis. Absidia the roots are on either side or the sporangia. Causes localized infections such as in burns, under dressings and also seen in IV drug users. Mucor the roots are absent. Mucor more frequently causes disseminated lesions such as rhinocerebral infections in diabetics with ketoacidosis or in patients with leukemia or neutropenia. These organisms result in a necrotizing cellulitis or a plaque or nodule with a necrotic eschar. The organisms invade the wall of blood vessels resulting in thrombosis and infarction. The organism in tissue displays irregular branching at 90 degree (right angle) and the hyphae are broad ribbon-like with no septae. The organism can be seen on H & E, but better with GMS.
- Which histologic subtype is most aggressive?
A. Solid
B. Nodular
C. Superficial
D. Morpheaform
E. All are equal
Correct choice: D. Morpheaform
Explanation: Morpheaform, micronodular and sclerosing are the most aggressive histologic subtypes of basal cell carcinoma. Superficial is the least aggressive.
- The patient just returned from a sunny vacation with this eruption. What is your diagnosis
A. rosacea
B. acute cutaneous lupus
C. phototoxic eruption
D. Porphyria cutanea tarda
E. seborrheic dermatitis
Correct choice: C. phototoxic eruption
Explanation: The epidermis is still a basket weave so this process happened acutely. There is no lymphocytic infiltrate that would be expected in lupus. We are not on sebaceous skin as would be expected for seborrheic dermatitis and rosacea. Porphyria cutanea tarta results in a subepidermal split with festooning of the dermal papillae.
- This tumor was excised from a verrucous yellow plaque on the scalp what is it?
A. Syringocystadenoma papilliferum
B. Eccrine acrospiroma
C. Hidradenoma Papilliferum
D. Tubular apocrine adenoma
E. Syringofibroadenoma
Correct choice: A. Syringocystadenoma papilliferum
Explanation: Syringocystadenoma Papilliferum: 33% arise in association with a nevus sebaceous, 10% may coexist with a BCC or trichoblastoma. A subset of cases has a deletion of 9q22 PTCH gene and 9q21 (p16). Histologically they present as surface invagination of glandular cords composed of one to two layers of cuboidal cells associated with a fibrovascular stroma with numerous plasma cells. Cystic spaces may form within which are free floating islands which are peripherally lined by cuboidal cells with an inner core composed of loose connective tissue, blood vessels and numerous plasma cells.
Papillary syringocystadenoma (syringocystadenoma papilliferum) is distinctive for its wide papillary fronds that are in continuity with the surface squamous epithelium. Syringocystadenomas are only rarely cystic. The fronds are lined by a bilayer, with basal cuboidal cells and apical columnar apocrine cells, and the cores of fronds virtually always contain a dense infiltrate of lymphocytes and plasma cells. A plasmacytic infiltrate commonly accompanies neoplasms of apocrine lineage, and thus the mere presence of plasma cells in a given lesion is not sufficient to confirm a diagnosis of syringocystadenoma.
At low magnification, papillary hidradenoma (hidradenoma papilliferum) consists of a well- circumscribed nodule within the dermis and usually lacks both a connection to the surface epithelium and the prominent plasmacytic infiltrate of syringocystadenoma papilliferum. Both tubules and papillary fronds are usually present, and broad elongated fronds with delicate fibrous cores are usually identifiable. Both tubules and fronds are usually lined by a bilayer, with basal cuboidal myoepithelial cells and apical apocrine cells, and the apical cells usually display a conspicuous holocrine secretion. At least some of the basal layer cells represent authentic myoepithelial cells with contractile function, and labeling of the myoepithelial layer through immunohistochemical staining for actin filaments can sometimes be of diagnostic value in the distinction from adenocarcinoma, which often lacks a complete myoepithelial layer.
- When this lesion occurs in multiples, which disorder should be suspected?
A. Rombo syndrome
B. Multiple Familial Trichoepithelioma
C. Goltz
D. Brooke-Spiegler syndrome
E. Carney complex
Correct choice: D. Brooke-Spiegler syndrome
Explanation: Patients with Brooke-Spiegler syndrome often have multiple spiradenomas, cylindromas, and trichoepitheliomas.
- This lesion most commonly metastasizes to which location?
A. Scalp
B. Arm
C. Leg
D. Back
E. Nose
Correct choice: A. Scalp
Explanation: Renal cell carcioma most commonly metastasizes to the scalp.
- What is your best diagnosis?
A. Lichen Trichophyticus
B. Secondary Lues
C. Lichen Nitidus
D. Scabies
E. Acral Hyperkeratosis
Correct choice: C. Lichen Nitidus
Explanation: A chronic inflammatory disease characterized by shiny, flat-topped, usually flesh- coloured micropapules no larger than the head of a pin. Lesions are localized in the early stages, found chiefly on the lower abdomen, penis, and inner surface of the thighs. Distribution may become generalized as the disease progresses.
Although the clinical presentation will suggest the diagnosis, lichen nitidus usually requires a skin biopsy to be confirmed. The histology of lichen nitidus is very typical and described as the ‘claw and ball’ appearance:
* Focal dense lymphohistiocytic infiltrate in the upper dermis very close to the epidermis.
* Langhans giant cells are often present in the infiltrate.
* Rete ridges of the epidermis are elongated and ‘clutch’ the infiltrate.
- Red blood cells are seen just under the epidermis in the hemorrhagic/purpuric form.
- Eosinophilic dermal material with some cell nuclei may be seen within the epidermis in the perforating variant.
- Calciphylaxis is characterized by intimal fibrosis and medial vascular calcification (that can become transmural) as well as transdifferentiation of vascular smooth muscle cells into osteoblast- like cells; these changes plus thrombosis lead to ischemic necrosis of the skin and soft tissues. Which of the following histological stains (shown below) would best highlight the medial vascular calcification and assist with making the diagnosis?
A. Sudan black
B. Verhoff Van Geisen
C. Von Kossa
D. Trichrome
E. Alcian blue
Correct choice: C. Von Kossa
Explanation: Calciphylaxis is characterized by intimal fibrosis and medial vascular calcification (that can become transmural) as well as transdifferentiation of vascular smooth muscle cells into osteoblast-like cells; these changes plus thrombosis lead to ischemic necrosis of the skin and soft tissues. Because calcium deposits may be subtle in H&E-stained sections, von Kossa and Alizarin red stains are used to increase detection.
1- Sudan black stains lipids in granulocytes.
2- Verfoeff-van Gieson stains elastic fibers black and outlines elastic lamina of muscular arteries and media of aorta. The background is trichrome.
4- Trichrome stains collagen blue.
5- Alcian blue is a common “routine” stain (not an immunohistochemical stain) to detect mucins.
- Which gene mutation and/or amplifications are more commonly found in this type of melanoma and mucosal sites than in melanomas on intermittently sun-exposed sites
A. NRAS
B. KIT
C. GNAQ
D. HRAS
E. PTEN
Correct choice: B. KIT
Explanation: KIT mutations and/or amplifications are more commonly found in melanomas located on acral and mucosal sites than in melanomas on intermittently sun-exposed sites.
- What is the neoplasm in this biopsy?
A. Chondroid syringoma
B. Papillary eccrine adenoma
C. Tubular apocrine adenoma
D. Eccrine acrospiroma
E. Trichoblastoma
Correct choice: A. Chondroid syringoma
Explanation: Chondroid Syringoma: Most commonly occurs in middle age males on the head and neck. Histologically this is a well circumscribed dermal tumor composed of dilated ducts, hyaline or
plasmacytoid cells (myoepithelial cells), keratinous cysts, +/- cells that show hair matricial differentiation occasionally with some areas of mature fat. All elements arise within a homogenous bluish chondromyxoid matrix (+ Type II collagen, + acid MPS stains with Alcian blue/green (stains at high and low PH) consistent with chondroitin sulfate). Focal calcification may occur.
Apocrine mixed tumors form a well circumscribed dermal mass. These distinctive tumors are composed of both a mesenchymal component which is usually chondroid, and an epithelial component. The cartilage is mature, with bland chondrocytes and a silver/grey matrix. The epithelium is bland, and consists in most areas of two cell layers: a myoepithelial layer and a lining luminal layer.
- A 35 year old man presents with this lesion shown in the photo on his hand. The patient undergoes a biopsy for confirmation of the diagnosis. What finding is specific for this condition?
A. Wedge-shaped perivascular lymphocytic infiltrate with eosinophils
B. Fibrinoid necrosis and leukocytoclasia
C. Collapsed keratin bundles
D. Peforating elastin, parakeratosis
E. Epithelial cells with cytoplasmic vacuoles
Correct choice:E. Epithelial cells with cytoplasmic vacuoles
Explanation: This is a wart, which on histology has epithelial cells with cytoplasmic vacuoles refered to as koilocytes. A. is seen with arthropod bites. B. is seen in cutaneous vasculitis. C. is in Darier. D. Elastosis perforans serpiginosa.
- What is the classic histologic finding?
A. Lichenoid infiltrate
B. Alternating ortho and parakeratosis
C. Mounds of parakeratosis
D. Coronoid lamella
E. Basaloid proliferations
Correct choice: D. Coronoid lamella
Explanation: This is disseminated superficial actinic porokeratosis. The classic histologic finding is a coronoid lamella which corresponds to the raised edge of the lesion.
- Histologically, this lesion shows plump, polygonal cells arranged in nests and fascicles with granular cytoplasm. Which immunohistochemical stain would be positive?
A. CD31
B. Synaptophysin
C. Factor XIIIa
D. S-100
E. CD34
Correct choice: D. S-100
Explanation: Granular cell tumors are benign growths which typically occur on the tongue. They are typically well-circumscribed, raised, firm nodules. Histologically, the cells have uniform nuclear characteristics and granular cytoplasm due to presence of lysozyme. These tumors are PAS positive and S-100 positive.CD31 stains positive in vascular neoplasms (e.g. angiosarcoma). Synaptophysin stains positive in neuroendocrine neoplasms (e.g. Merkel cell carcinoma). Factor XIIIa stains positive in dermatofibroma, xanthoma disseminatum, fibrous papule, atypical fibroxanthoma, and xanthogranuloma. CD34 stains positive in vascular tumors (benign/malignant), dermatofibrosarcoma protuberans, neurofibroma, epithelioid sarcoma, spindle cell lipoma, and fibrous papule.
- What is this neoplasm?
A. Hibernoma
B. Malakoplakia
C. Myospherulosis
D. Liposarcoma
E. Pleomorphic lipoma
Correct choice: A. Hibernoma
Explanation: Hibernoma: This is a rare neoplasm that typically occurs in 30-40 year old males as a slowly enlarging warm mass on scapular region, trunk, axilla or thigh. There are also myxoid & spindle cell variants that occur on the posterior neck/shoulder. The lesion enhances with contrast on CT and MRI fails to reveal fat septations which differs for that seen with other lipomas. Abnormalities in 11q13 and loss of MEN1 gene on 10q22 have been noted. Histologically: The lesion is composed of large polygonal adipocytes that have with multiple vacuoles and an eosinophilic granular cytoplasm with a central nucleus and prominent nucleolus. These cells are
referred to as “Mulberry cells.” Admixed among these larger adipocytes are smaller cells with a granular cytoplasm, mature white fat and some times spindle cells.
- A 56-year-old Mexico-born man, currently residing in New Mexico, presents with a one-year history of the rash shown. He also complains of distal extremity numbness. A punch biopsy is performed and a special stain is performed and shown in the second image. Which of the following stains were performed to best visualize the organisms found in this image?
A. Brown and Brenn
B. Giemsa
C. Periodic Acid-Schiff
D. Wade-Fite
E. Warthin-Starry
Correct choice: D- Wade-Fite
Explanation: The clinical scenario and image are most consistent with lepromatous leprosy. The Wade-Fite stain is used to stain the acid-fast bacilli. The Fite stain highlights mycobacteria in general but is specifically used to identify mycobacterium leprosum. The stronger acid used in the Ziehl-Neelsen stain is deemed too harsh for M. leprae and the lipid in the cell’s membrane is washed away, making visualization of the organism difficult. Fite uses a weaker acid in the decolorization phase of the procedure, preserving the more delicate cell walls of the organism. The Fite and the Ziehl-Neelsen methods share their positive acid-fast profiles; red is read as a positive stain.
Brown and Brenn is a tissue Gram stain that is a practical method of identifying and differentially staining bacteria. Giemsa stain is primarily used to stain mast cells, but can also stain certain organisms– spirochetes, protozoans, and cutaneous Leishmania in particular. Periodic Acid-Schiff accentuates fungal cell walls. Warthin-Starry is used chiefly in the identification of spirochetes in diseases such as syphilis, Lyme disease, and acrodermatitis chronica atrophicans. A positive stain will reveal black spirochetes.
- The most likely diagnosis of this image is which of the following?
A. lipodermatosclerosis
B. sclerema neonatorum
C. erythema nodosum
D. lupus profundus
E. subcutaneous fat necrosis of the newborn
Correct choice E. subcutaneous fat necrosis of the newborn
Explanation: Subcutaneous fat necrosis of the newborn is easily recognized by the intense inflamation, radially arranged eosinophilic crystals in the fat cells, and the foreign body giant cells, in comparison to sclerema neonatorum, where there is no inflammation as the patient is too sick to mount a response.
- This tumor was excised from the scalp of an older woman, what is this neoplasm?
A. Cylindroma
B. Sebaceous carcinoma
C. Pilomatricoma
D. Basal cell carcinoma
E. Spiradenoma
Correct choice:A. Cylindroma
Explanation: Cylindroma: Most often seen in middle age females on the scalp. Multiple lesions can be associated with trichoepitheliomas, spiradenoma and adenomas of parotid gland in Brooke Spieler syndrome. Histologically this is a poorly circumscribed dermal tumor with multiple small irregularly shaped basophilic islands often likened to puzzle pieces composed of a peripheral layer
of smaller darker cells, with cells that have increased eosinophilic cytoplasm centrally. Each island is surrounded by a thick eosinophilic cuticle (type IV and VII collagen), with similar eosinophilic hyaline droplets seen within the island.
Low power view of cylindroma shows a non-encapsulated tumor nodule arising from the dermis. This is formed by multiple irregular tumor islands, distributed in an aptly named ‘jigsaw’ pattern. Surrounding the tumor islands, and in discrete droplets within the nodules is a thick hyaline deposit. Two populations of cells are noted to make up the tumor nodules. A smaller cell with a hyperchromatic nucleus tending to the periphery, and larger cells with open nuclei throughout the centre of the nodules.
- A nodule is biopsied from a 70 year old woman’s arm. The histology is shown here. What is the diagnosis best stained with?
A. CD56
B. CEA
C. S-100
D. CD31
E. CK5-6
Correct choice: A. CD56
Explanation: Merkel cell carcinoma stains positive with neuron-specific enolase, epithelial membrane antigen, CD56, neurofilament, synaptophysin, chromogranin, argyrophil. The most widely and accepted marker is CK20 (perinuclear dot staining), and CK8/18/19 (CAM 5.2) is
another uniformly good choice. However, CD56 is more intensely positive (cell membrane staining).
- This neoplasm tends to occur most frequently on which anatomic region?
A. Sun-exposed areas of the head and neck
B. Genital region
C. Acral sites
D. Oral mucosa
E. Extremities
Correct choice: A. Sun-exposed areas of the head and neck
Explanation: Lentigo maligna tends to occur most frequently in the head and neck region in sun- exposed areas.
- A patient presents with this path and erythema nodosum and iritis. What is their likely diagnosis?
A. Lofgren Syndrome
B. Heerfordt Waldenstrom syndrome
C. darrier-roussy syndrome
D. blau syndrome
E. mikulicz syndrome
Correct choice: A. Lofgren Syndrome
Explanation: Lofgren syndrome makes you SMILE: Sarcoid, migratory polyarthritis, iritis, LAD (hilar), EN, because you laugh and grin.
- What exogenous material is shown here?
A. Calcium hydroxylapatite
B. Hyaluronic acid filler
C. Suture
D. Gelfoam
E. Poly-L-lactic acid
Correct choice:D .gelfoam
Explanation: Gelfoam is present in this tissue specimen. Gelfoam has a characteristic appearance with slightly basophilic honeycomb or collapsed net-like deposits.
- A 58-year-old man presents with grouped erythematous nodules located around his ears that are occasionally painful and pruritic. A biopsy showed proliferations of capillary-sized vessels with epithelioid endothelial cells surrounding larger, thick-walled vessels accompanied by eosinophils and lymphocytes. Which is the most likely diagnosis?
A. Angiolymphoid hyperplasia with eosinophilia
B. Kimura disease
C. Sarcoidosis
D. Lymphoma cutis
E. Epithelioid hemangioendothelioma
Correct choice A. Angiolymphoid hyperplasia with eosinophilia
Explanation: Angiolymphoid hyperplasia with eosinophilia is characterized by benign angiomatous nodules or plaques, often multiple and grouped. They are usually located in the head and neck, especially around the ears. The lesions may be painful, pruritic or pulsatile. Histologically they are characterized by proliferations of capillary-sized vessels with epithelioid endothelial cells surrounding larger, thick-walled vessels, accompanied by eosinophils and lymphocytes. Although rare instances of spontaneous regression have been reported, surgical excision is generally required.
2 – ALHE (angiolymphoid hyperplasia with eosinophilia) may resemble Kimura disease, which is now considered to be a separate entity, is usually located on the posterior neck and histologically has much larger lymphoid follicles. 3 – ALHE can resemble sarcoidosis clinically but has different histological features. Sarcoidosis is characterized by “naked” non-caseating granulomas in the dermis and subcutaneous tissues. 4 – ALHE can resemble lymphoma cutis clinically but has different histological features. Lymphoma cutis shows a mixture of B and T lymphocytes with benign immunohistochemistry. 5 – ALHE can resemble epithelioid hemangioendothelioma but is distinguished histologically. Epithelioid hemangioendothelioma is characterized by poorly canalized cords and nests of endothelial cells forming small intracytoplasmic vacuoles as a sign of primitive vascular differentiation.
- What is the most likely diagnosis?
A. tinea versicolor
B. tinea nigra
C. candida
D. sporothrixosis
E. chromomycosis
Correct choice: A. tinea versicolor
Explanation: Tinea veriscolor has the typical spaghetti and meatballs as seen here, the hypae and spores. Tinea nigra is pigmented.
- You would expect this neoplasm to:
A. Be painful on palpation
B. Have a high metastatic rate and poor prognosis
C. Disseminate to the skin from an internal focus
D. Dimple on lateral palpation
E. Have mutations in the SHH/PTCH signaling pathway
Correct choice: A. Be painful on palpation
Explanation: Eccrine Spiradenomas are classically painful to palpation and are in the BLUE ANGEL mnemonic for painful dermal nodules: Blue Rubber Bleb Nevus Syndrome Angiolipomas Neuromas Glomus tumors Eccrine Spiradenomas Leiomyomas
- This material is formed during which stage of wound healing?
A. Inflammatory
B. Proliferative
C. Remodeling
D. Contraction
E. Vasoconstrictive
Correct choice: B. Proliferative
Explanation: Granulation tissue forms during the proliferative phase of wound healing.
- What type of reaction is demonstrated here?
A. Connective tissue
B. Psoriasiform
C. Lichenoid
D. Foreign body
E. Neoplastic
Correct choice: D. Foreign body
Explanation: A foreign body reaction develops in response to the deposition of foreign material or altered endogenous material in the dermis. Granulomatous inflammation with histiocytes and multinucleate giant cells forms around the material. Tattoo pigment is present in this particular case.
- What is the best diagnosis?
A. Psoriasiform
B. Dermatitis Herpetiformis
C. Angiolymphoid Hyperplasia with Eosinophilia
D. Lichen Nitidus
E. Ochronosis
Correct choice: C. Angiolymphoid Hyperplasia with Eosinophilia
Explanation: Angiolymphoid Hyperplasia with Eosinophilia(EPITHELIOID HEMANGIOMA) consists of solitary or multiple benign cutaneous nodules comprised of immature and mature vascular structures intermingled with endothelial cells and a varied infiltrate of eosinophils, histiocytes, lymphocytes, and mast cells.
Angiolymphoid hyperplasia with eosinophilia is an apparently non-malignant, locally proliferating lesion composed of channels of small blood vessels surrounded by lymphocytes and eosinophils (these are two types of white blood cell). Angiolymphoid hyperplasia with eosinophilia is also known as epithelioid or histiocytoid haemangioma.
Kimura disease is probably distinct from angiolymphoid hyperplasia with eosinophilia. In Kimura disease the lesions are deeper-seated, with no initial overlying skin lesions. In angiolymphoid hyperplasia with eosinophilia the lesions are smaller and characterised by thick-walled so-called histiocytoid or epithelioid blood vessels.
Angiolymphoid hyperplasia with eosinophilia has been reported from many parts of the world but appears to be particularly common in Japan.
- What is this neoplasm?
A. Sclerotic fibroma
B. Angiofibroma
C. Keloid
D. Neurofibroma
E. Dermatofibroma
Correct choice A. Sclerotic fibroma
Explanation: Sclerotic Fibroma (circumscribed storiform collagenoma): This can occur as an isolated lesion n the head or neck or upper extremities, but multiple lesions are associated with Cowden’s disease which is an AD disorder linked to a mutation of PTEN on chromosome 10p. Histology: Dome shaped papule with an overlying attenuated epidermis. A well-circumscribed nodule composed of thickened homogenous collagen that is arranged in whorls with a thumbprint or grains of wood appearance is seen in the dermis. Overall the lesion exhibits low cellularity and the elastic fibers are absent. The tumor stains positively with vimentin, Factor XIIIA and focally for CD34.
- You diagnose a patient with multiple epidermal tumors that on histopathology shows a fibrous pink orb with epithelial strands coming through the follicular center. The patient most likely has a mutation in which gene?
A. CYLD
B. p53
C. FLCN
D. RAS
E. ECM1
Correct choice: C. FLCN
Explanation: This describes a fibrofolliculoma, a tumor seen in Birt-Hogg-Dubé syndrome. This is an autosomally dominant syndrome due to a mutation in FLCN - folliculin (Choice 3), a tumor suppressor gene. Patients show these skin lesions and have an increased risk for renal cell carcinoma, spontaneous pneumothoraces, pulmonary cysts, and medullary carcinoma of the thyroid.
CYLD is mutated in Brooks-Spiegler syndrome, characterized by multiple adnexal tumors often located on the scalp. p53 is an important tumor suppressor gene, mutations of which lead to tumor syndromes such as Li-Fraumeni syndrome. The p53 gene product is inhibited by the E6 gene product of HPV, which is a major virulence factor of HPV. RAS is an oncogene which is inappropriately activated in diseases such as Neurofibromatosis, leading to multiple tumors. ECM1 is a gene which is mutated in Lipoid proteinosis. Autoantibodies to ECM-1 are seen in Lichen Sclerosus.
213- The large cells are most likely to stain positively for which marker?
A. CD30
B. S100
C. Neuron specific enolase
D. CD20
E. Amyloid
Correct choice: A. CD30
Explanation: The image is of lymphomatoid papulosis with the “lumps of coal” cells in the dermis. The histologic architecture can be similar to PLEVA but with wedge-shaped infiltrate and atypical lymphocytes. Eosinophils and neutrophils are also intermixed. These cells are CD30+.
S100 can be positive in melanoma and Langerhans Cell Histiocytoses. Neuron specific enolase is positive in merkel cell, carcinoid tumors, and melanoma. CD20 is positive in Primary Cutaneous Follicle Center Lymphoma. Amyloid is positive in Amyloidosis
214- A patient presents with a few of these lesions and some hyperkeratotic papules on his anterior shins. What diagnositic test should the patient undergo?
A. Colonoscopy
B. Cystoscopy
C. Bronchoscopy
D. Cortisone stimulation test
E. Otoscopy
Correct choice: A. Colonoscopy
Explanation: The image is a sebaceous adenoma, and the question describes keratoacanthomas on the anterior shin, thus this patient should undergo colonoscopy to evaluate for colon cancer. Given this constellation of symptoms one must evaluate for Muir-Torre syndrome.
215- This is a DIF image of a case of lichen planus (anti-fibrin ab)
? What does the image show?
A. Shaggy deposition of fibrin
B. Granular deposits in dermal papillae
C. Linear deposits of IgG at DE junction
D. Vascular deposition
E. Dermal mucin
Correct choice: A. Shaggy deposition of fibrin
Direct immunofluorescence of lichen planus reveals immunoglobulin (mainly IgM), complement, and fibrin staining of colloid bodies in the deeper epidermis and superficial dermis. Although the findings are characteristic of LP, direct immunofluorescence of classic LP is not necessary
Lichen planus - histologic features
Compact hyperkeratosis, usually no parakeratosis except when rubbed or oral Hypergranulosis, often wedge-shaped
Irregular acanthosis with “saw-toothed” rete ridges rarely epidermal atrophy Colloid bodies often
Liquefaction degeneration of the basal layer Lichenoid lymphocytes in the papillary dermis Melanin incontinence often
218- What diagnosis is shown here?
A. Lipodermatosclerosis
B. Erythema nodosum
C. Pancreatic panniculitis
D. Lupus profundus
E. Erythema induratum
►B
On histology, erythema nodosum is characterized by a septal panniculitis with septal thickening and granulomatous inflammation.
237- What type of lesion is shown here?
A. Chondroid syringoma
B. Hidradenoma
C. Trichoblastoma
D. Cylindroma
E. Spiradenoma
►E
On histology, a spiradenoma is a dermal nodule composed of basaloid cells in a trabecular pattern. Two cell types are usually present: small basaloid cells and larger cells with pale nuclei.
244- What neoplasm is pictured here?
A. Trichoadenoma
B. Tumor of the follicular infundibulum
C. Cutaneous lymphadenoma
D. Desmoplastic trichoepithelioma
E. Syringoma
►D
Desmoplastic trichoepitheliomas are composed of small cords and islands of basaloid cells within a fibrous stroma. Keratinous cysts are often present.
250- This was excised from the face, what is this neoplasm ?
A. Syringoma
B. Trichoadenoma
C. Basal cell carcinoma
D. Desmoplastic trichoepithelioma
E. Microcystic adenocarcinoma
►A
Syringomas on the eyelids, cheeks, chests and can be eruptive and increased numbers in Down’s syndrome and a clear cell change has been associated with diabetes. Histologically this i s a dermal tumor consisting of eccrine ducts, lined by two cell layers sometimes creating a tad pole appearance, there can also be small basaloid islands or strands of cells. Within the lumens of the ducts is eosinophilic material, the lumens are CEA+. The tumor is located superficially and fails to display perineural extension as is seen in MAC. The glands are associated with a fibrous sclerotic stroma, usually no (or minimal) keratin cysts or foreign body granulomas as seen in desmoplastic trichoepithelioma. Enlargement of the glandular cells more of a clear or vacuolated cytoplasm can be seen in patients with diabetes.
253- What is the diagnosis?
A. Lichen planus-like keratosis
B. Malignant melanoma
C. Syphilis
D. Spitz nevus
E. Halo nevus
►E
A halo nevus is characterized by a symmetric proliferation of nevus cells in the dermis, surrounded by an intense lymphocytic infiltrate.
254- Which genetic abnormality has been found in the cells of this neoplasm?
A. t(17;22)
B. BRAF V600E mutation
C. NRAS mutation
D. t(9;22)
E. KIT mutation
►A
Dermatofibrosarcoma protuberans has been associated with reciprocal translocations of chromosomes 17 and 22, t(17;22). This rearrangement fuses the collagen type I alpha 1 (COL1A1) and the PDGF-beta chain (PDGFB) genes.
258- This eruption is mediated by antibodies to which structure?
A. Desmoglein 1
B. Desmoplakin
C. Collagen VII
D. BP180
E. Desmoglein 3
►D
Bullous pemphigoid is most often associated with antibodies to BP180.
261- This lesion typically occurs in which population?
A. Children on the legs
B. Middle-aged on the face
C. All ages on the trunk
D. Elderly on the head and neck
E. Infants on the trunk
►D
Atypical fibroxanthomas develop in elderly patients primarily on the highly sun-damaged skin of the head and neck. The prognosis is usually very good despite the pleomorphic histo logy which is characterized by very bizarre, atypical spindle-shaped and anaplastic cells with numerous mitoses.
263- What material is found inside multinucleated giant cells in this condition?
A. Calcium
B. Red blood cells
C. White blood cells
D. Collagen fibers
E. Elastic fibers
►E
Annular elastolytic giant cell granuloma presents as multiple papules and annular plaques. On histology, there is granulomatous inflammation with multinucleated giant cells demonstrating elastophagocytosis
264- What infection does this patient have?
A. Cryptococcosis
B. Blastomycosis
C. Coccidioidomycosis
D. Histoplasmosis
E. Leprosy
►C
Lesions of cutaneous coccidioidomycosis demonstrate non-caseating granulomas in the dermis, often with overlying pseudoepitheliomatous hyperplasia. Thick walled spherules of C. immitis are found within multinucleated giant cells and granulomas.
277- What is the best diagnosis?
A. Keloid
B. Ochronosis
C. Lichen Nitidus
D. Compound Spitz Nevus
E. Dermatitis Herpetiformis
►A
Distinguishing hypertrophic scar (HS) from keloid histopathologically is sometimes difficult because thickened hyalinized collagen (keloidal collagen), the hallmark of keloid, is not always detectable and [alpha]-smooth muscle actin ([alpha]-SMA), a differentiating marker of HS, is variably expressed in both forms of scar.
282- Which of the following is characteristic of Birt-Hogg-Dube Syndrome?
A. Autosomal recessive mode of inheritance
B. Multiple trichoepitheliomas
C. Caused by mutation in hamartin
D. Multiple trichodiscomas
E. Colon cancer common
►D
Birt-Hogg-Dube Syndrome (BHD) characterized by multiple small harartomas of mesodermal component of hair discs, which were indentified as trichodiscromas. It is an autosomal dominant disease caused by mutations in folliculin. Patients with multiple fibrofolliculomas may also have acrochordons, collagenomas, lipomas, and/or oral fibromas. BHDS recently has been reported in association with various types of renal tumors, such as oncocytoma and a variant of papillary renal cell carcinoma. There are no trichoepitheliomas in BHD syndrome.
289- What is this neoplasm?
A. Poroma
B. Eccrine acrospiroma
C. Sebaceous adenoma
D. Basal Cell Carcinoma
E. Trichoblastoma
►A
Poroma: Palmar/plantar skin, trunk and lower extremities. Named based upon location, If purely intraepidermal called a hidroacanthoma simplex, if only in the dermis it is a dermal duct tumor, but more commonly seen both in the epidermis and dermis and then it is given general classification as
poroma. Associated with Schopf-Schultz-Passarge syndrome and Clouston’s syndrome. Histologically composed of a proliferation of small uniform cuboidal basaloid cells that are PAS+DS (i.e. contains glycogen). The cells are smaller than neighboring keratinocytes. The tumors can be pigmented and there can be necrosis en mass. The latter finding is an exception to the general rule that benign tumors do not show necrosis en mass.
290- This lesion is defined by the presence of what material in the dermis?
A. Amiodarone
B. Ink
C. Iron
D. Melanin
E. Carbon
►D
A blue nevus is characterized by the presence of dendritic melanocytes and melanophages.
293- What is this neoplasm?
A. Pilomatricoma
B. Proliferating pilar tumor
C. Trichoepithelioma
D. Basal cell carcinoma
E. Eccrine acrospiroma
►A
Pilomatrixoma (Calcifying epithelioma of Malherbe): Found on the head, neck and upper extremities in the first 2 decades of life. Typically solitary but multiple pilomatricomas arise in several syndromes. Even in isolation these tumors may arise due to activating mu tations in the beta-catenin gene. Histologically: This tumor consists of two major cell types plus an intermediate or transitional cell type. Initially the tumor is more cystic with the cells at the periphery of the tumor that are more basophilic with indistinct cell borders and little cytoplasm. The cells have hyperchromatic nuclei and often normal mitoses can be appreciated. Centrally there are eosinophilic
―ghost or shadowǁ* cells which are cells that have undergone terminal differentiation. These cells have more distinct borders, increased cytoplasm but only a ghost of a nucleus. Then there are cells that reside somewhere in between these two cell types. The proportion of these cells varies depending on the stage of the lesion; i.e younger lesions have more basophilic cells and appear more cystic, older lesions have a greater component of ghost cells and up to 20% of lesions on removal are completely composed of ghost cells.
294- The presence of which cell type confirms this diagnosis?
A. Lipidized histiocyte
B. Mast cell
C. Multinucleate keratinocyte
D. CD30+
E. Langhans giant cell
►C
Herpes infection is confirmed by the presence of multinucleate keratinocytes which often have intranuclear inclusion bodies.
299- What underlying disease does this patient have?
A. Wiskott-Aldrich syndrome
B. PHACES
C. Osteogenesis imperfecta
D. Darier’s disease
E. Vitiligo
►C
Elastosis perforans serpiginosa is associated with an underlying condition in up to a third of cases. Some of these conditions include osteogenesis imperfecta, Ehlers-Danlos syndrome, Marfan’s syndrome, acrogeria, scleroderma, and Down syndrome.
300- What is the diagnosis?
A. Marjolin’s ulcer
B. Lichen planus
C. Basal cell carcinoma
D. Lichen amyloid
E. Dermatofibroma
►A
Marjolin’s ulcer is an aggressive ulcerated squamous cell carcionoma that arises due to chronic inflammation. The image shows the invasive atypical keratinocytes. In lichen amyloid there are pink amorphous deposits that do not have nuclei.
302- This eruption is mediated by autoantibodies to which antigen?
A. Desmoplakin
B. Desmoglein 1
C. BP230
D. Collagen VII
E. BP180
►D
Bullous systemic lupus erythematosus is mediate by antibodies to collagen VII. Histology is similar to that of linear IgA bullous dermatosis and dermatitis herpetiformis.
309- What is this neoplasm?
A. Trichoadenoma
B. Trichoblastoma
C. Trichoepithelioma
D. Basal cell carcinoma
E. Nevus comedonicus
►A
Trichoadenoma: A nodule on the face or buttock that is slightly depressed. Typically confined to the upper dermis and composed of multiple milia or infundibular-like cysts that have a squamous epithelial lining associated with a granular layer and central flakey keratin in the lumen . The stroma can be sclerotic. The lesion is composed primary of cysts with a few thin strands of basaloid cells; if basaloid strands predominate with only a few cysts then lesion is a trichoepithelioma.
314- Which type of lymphoma with an excellent prognosis is shown here?
A. Follicuar
B. Marginal zone
C. Diffuse large B-cell
D. Cutaneous T-cell
E. NK/T-cell
►A
Follicular lymphoma demonstrates a nodular or diffuse infiltrate involving the dermis and sometimes the subcutis. There may be a follicular, follicular and diffuse, or a diffuse pattern of atypical B-cells.
315- This was a deep seated large tumor in the thigh, what is it?
A. Liposarcoma
B. Nodular fascitis
C. Hibernoma
D. Spindle cell lipoma
E. Pleomorphic lipoma
►A
A liposarcoma is one of the most common sarcomas to occur in adults, 50-70yos. Those that occur in resectable regions (like the thigh) have a good prognosis; those that occur in retroperitoneum, mediastinum or spermatic cord recur repeatedly and have a risk to dedifferentiate with a mortality approaching 80% over the following 10-20 years. It has a characteristic supernumerary ring with amplification of 12q14 MDM2 region. Histologically The adipocytes vary in size throughout the tumor. Pleomorphism is variable depending upon the degree of differentiation that the tumor displays. The nuclei of the more well-differentiated adipocytes, as well as, the spindled cells are hyperchromatic with nuclear atypia. The presence of lipoblasts, i.e. either mono-vacuolated signet ring type of lipoblast as is more commonly seen in myxoid liposarcoma and/or multi-vacuolated lipoblasts with central nuclei scalloped by vacuoles, are characteristic of a liposarcoma, but are not necessary to make the diagnosis. There is often a plexiform proliferation of blood vessels, with an appearance that has been likened to crow’s feet or chicken wire. The stroma can be loose and delicate, fibrous or myxoid. Thick ropey fibrous septae are common in liposarcoma and in lipoblastoma.
320- This characteristic change of the fat is characteristic of which panniculitis?
A. Subcutaneous panniculitis like T cell lymphoma
B. Lupus panniculitis
C. Sclerosing panniculitis
D. Pancreratic panniculitis
E. Calciphylaxis
►B
Lupus panniculitis is characterized by hyalinization of the fat with a lymphoplasmocytic infiltrate, as depicted here. It is a lobular panniculitis without vasculitis. The other answer choices are other lobular panniculitidies. Subcutaneous panniculitis like t cell lymphoma has atypical cells rimming the fat lobules. Sclerosing panniculitis is lipodermatosclerosis which has lipomembranous change. Pancreatic panniculitis has liquefactive fat necrosis and saponificatoin of the fat. Calciphylaxis has calium deposites in the walls of tbe blood vessels.
322- Scalp biopsy of a 54-year-old female with suspected lichen planopilaris would likely reveal inflammation around which portion of the hair follicle:
A. Dermal papilla
B. Hair bulb
C. Matrix
D. Isthmus
E. Infundibulum
►E
On biopsy, alopecia areata exhibits a peribulbar lymphocytic ―swarm of bees.ǁ Discoid lupus typically exhibits inflammation surrounding the isthmus, along with a perivascular dermatitis and vacuolar interface changes. Lichen planopilaris exhibits inflammation most densely concentrated about the infundibulum.
325- This is an H and E stained slide, what is the organism?
A. Exophiala jeanselmei
B. Chromomycosis
C. Nocardia
D. Zygomycosis
E. Mucormycosis
►A
Phaeohyphomycotic cyst: Typically the result of an opportunist infection caused by being impaled by a splinter contaminated with a dematiaceous or pigmented fungus. Most commonly seen on distal extremities and results in a dermal abscess with fibrous tissue and granulomas within which are pigmented hyphae and yeast. The most common organism is Exophiala jeanselmei (yellow- brown septae hypha) and Wangiella dermatitidis. Histology: Circumscribed cyst with a fibrous wall within which is a chronic granulomatous reaction or dermal abscess, a splinter is sometimes seen along with the brown filamentous hyphae and yeast.
327- Which of the following histological features would be most helpful in differentiating lichenoid drug eruption from lichen planus?
A. Civatte bodies
B. Parakeratosis and eosinophils
C. Squamatization of the basal layer
D. Presence of pruritus
E. Band-like infiltrate with ―Saw-toothǁ rete ridges
►B
Lichenoid drug eruptions share clinical and histopathologic features with lichen planus. Sometimes differentiation is not possible; however, eosinophil, parakeratosis, and a deeper perivascular infiltrate is more suggestive of lichenoid drug. Implicated medications include captopril, penicillamine, and chloroquine.
331- Which gene mutation and/or amplifications are more commonly found in this type of melanoma and mucosal sites than in melanomas on intermittently sun-exposed sites?
A. NRAS
B. KIT
C. GNAQ
D. HRAS
E. PTEN
►B
KIT mutations and/or amplifications are more commonly found in melanomas located on acral and mucosal sites than in melanomas on intermittently sun-exposed sites.
333- What type of lymphoma is shown here?
A. Follicle center cell
B. Intravascular large B-cell
C. Marginal zone
D. Cutaneous T-cell
E. NK/T-cell
►B
Intravascular B-cell lymphoma is characterized by the presence of large, atypical cells partially or fully occluding blood vessels in the dermis and subcutis. The prognosis is very poor.
334- What is the diagnosis?
A. Squamous cell carcinoma
B. Trichilemmoma
C. Poroma
D. Pilar sheath acanthoma
E. Inverted follicular keratosis
►E
An inverted follicular keratosis is a benign tumor of the follicular infundibulum. On histology, they demonstrate tumor lobules composed of central squamous cells and peripheral basaloid cells. Squamous eddies are commonly noted.
- A- patient presents with a few of these lesions and some hyperkeratotic papuleson his anterior shins. What diagnositic test should the patient undergo?
A. Colonoscopy
B. cystoscopy
C. bronchoscopy
D. cortisone stimulation
E. otoscopy
►A
The image is a sebaceous adenoma, and the question describes keratoacanthomas on the anterior shin, thus this patient should undergo colonoscopy to evaluate for colon cancer. Given this constellation of symptoms one must evaluate for muir torre syndrome.
337- This clinically raspberry-like papilloma occurs in which syndrome?
A. Goltz
B. Rothmund-Thomson
C. Incontinentia pigmenti
D. Hermansky Pudlak
E. CHILD
►A
Goltz syndrome is characterized by distinct raspberry-like papillomas at junctions of mucosa and skin. Other findings include the following: skin atrophy, ulcerations, hernialike outpouchings of fatty tissue, syndromic facies, and lobster claw deformity.
341- This biopsy was obtained from an annular pigmented plaque on the trunk, what is this neoplasm?
A. Targetoid hemosiderotic hemangioma
B. Glomeruloid hemangioma
C. Angiosarcoma
D. Kaposi’s sarcoma
E. Tufted hemangioma
►A
Targetoid Hemosiderotic Hemangioma: Occurs most commonly on young adult males on the trunk and named for its clinical appearance. The lesion typically appears as a plaque with concentric rings, there is violaceous central region surrounded by a ring of pallor which is then surrounded by an erythematous or brown rim. Histologically in the superficial dermis there are dilated blood vessels, some of which have plump hobnailed endothelial cells. In the deeper dermis the vessels have a narrower lumen and dissect between the collagen bundles. Often within the lesion there are extravasated red blood cells and hemosiderin.
345- a pregnant woman <15 weeks presents with pink scaly patches all over her body and has this pathology, what is she at risk for?
A. LGA
B. death
C. SGA
D. Premature delivery
E. SIDS
►D
If pityriasis rosea occurs in women <15 weeks pregnant, they are at risk for premature delivery and neonatal hypotonia.
347- This presented as a papule with a tuft of hair on the face, what is this neoplasm?
A. Trichofolliculoma
B. Trichoepithelioma
C. Fibrous Papule
D. Acrochordon
E. Fibrofolliculoma
►A
Trichofolliculoma: Most often occurs on the face as a papule with a tuft of hair. Histologically composed of a central dilated large follicle (Mama hair), from which many secondary smaller hair follicles radiate (Baby hairs), with the entire unit often enveloped in a vascularized fibrotic stroma. If sebaceous glands are associated with the hair follicles then the term used is a sebaceous trichofolliculoma or a Folliculosebaceous cystic hamartoma. Within the mesenchymal stroma there are increased CD34 and factor XIIIA fibroblasts and Merkel cells as is seen in the ORS of the follicles.
349- These skin changes are caused by which type of trauma?
A. Cryotherapy
B. Thermal burn
C. Electrocautery
D. Chemotherapy
E. Ultraviolet radiation
►B
The histology of thermal burns include epidermal and dermal necrosis, thrombosis of blood vessels, destruction of pilosebaceous units, fusion of the collagen bundles and a sparse inflammatory cell infiltrate. Electrocautery effect often shows vertical elongation of keratinocytes and homogenization of dermal collagen. Topical chemotherapy will result in bizarre keratinocyte mitoses. Ultraviolet radiation will result in necrotic keratinocytes. Cryotherapy will cause the epidermis to become homogenous and a subepidermal bulla to form.
-This lesion was excised from the face, what is this neoplasm?
A. Clear cell syringoma
B. Sebaceous carcinoma
C. Microcystic adenocarcinoma
D. Renal cell carcinoma
E. Clear cell hidradenoma
►A
Syringoma: Multiple eyelids, cheeks, chests, can be eruptive and increased numbers in Down’s syndrome and a clear cell change has been associated with Diabetes. Histologically this is a dermal tumor consisting of eccrine ducts, lined by two cell layers sometimes creating a tad pole appearance, there can also be small basaloid islands or strands of cells. Within the lumens of the ducts is eosinophilic material, the lumens are CEA+. The tumor is located superficially and fails to display perineural extension as is seen in MAC. The glands are associated with a fibrous sclerotic stroma, usually no (or minimal) keratin cysts or foreign body granulomas as seen in desmoplastic trichoepithelioma. Enlargement of the glandular cells more of a clear or vacuolated cytoplasm can be seen in patients with diabetes.
A- biopsy was obtained from the nasal mucosa, what are the organisms in this biopsy?
A. Rhinosporidium
B. Coccidioidomycosis
C. Prototheca wickerhamii
D. Histoplasmosis capsulatum
E. Cryptococcus neoformans
►A
Rhinosporidiosis originally thought to be due to a fungus Rhinosporidium seeberi, now believed to be caused by an aquatic protistan parasite or Cyanobacteria, Microcystics aeruginosa. Sri Lanka & South America polypoid nasal/mucosal lesions in males and conjunctival lesions in females. Obtained from water or soil. Histology: granulomatous dermatitis with mixed inflammatory cell infiltrate with large thick walled birefringent sporangia which mature toward the center of a cyst, the organism measures 10-200 microns contain 7-8 micron endospores which contain eosinophilic globules. Watery environments causes cyst to rupture.
357- What lesion is shown here?
A. Chondroid syringoma
B. Hyaluronic acid filler nodule
C. Glomus tumor
D. Myofibroma
E. Scleromyxedema
►C
Glomus tumors show aggregates of glomus cells surrounding numerous blood vessels within a fibrous and sometimes myxoid stroma.
359- What is the diagnosis of this neoplasm?
A. Fibroma of tendon sheath
B. Dermatofibroma
C. Dermatofibrosarcoma protuberans
D. Spindle cell lipoma
E. Leiomyoma
►A
Fibroma of tendon sheath is a solitary, slow-growing tumor that is usually located on the hands, wrists or fingers of middle-aged individuals. Spindle or stellate cells are embedded in a dense fibrocollagenous stroma. This lesion demonstrates characteristic dilated or slit-like vascular channels.
361- The mutated product in Darier’s disease is:
A. SPINK5
B. SERCA2
C. ATP2A2
D. ATP2C1
E. SPINK5 and ATP2A2
►B
In Darier’s disease, the ATP2A2 gene encoding the SERCA2 Ca(2+)-ATPase is mutated in some patients. SPINK5 is the gene that is mutated in some patients with Netherton’s syndrome, and this gene the serine protease inhibitor LEKTI. ATP2C1 is the gene mutated in some patients with Hailey-Hailey disease.
364- Cicatricial pemphigoid antibodies directed against this are associated with high frequency of malignancy:
A. Laminin 5
B. Laminin 6
C. Beta4-integrin
D. BPAg2
E. All of these answers are correct
►A
Anti-laminin 5 cicatricial pemphigoid (CP) is also known as anti-epiligrin CP. Anti-epiligrin CP is associated with an increased frequency of internal adenocarcinomas. Laminin 5 is composed of three chains (heterotrimer), alpha3, beta3, gamma2. Antibodies are frequently directed against the alpha3 chain, and so cross-reactivity can be observed with laminin 6, as laminin 6
(alpha3beta1gamma1) has the alpha3 chain as well. Beta4-integrin antibodies have been associated with ocular CP. BPAg2 antibodies are seen in CP patients that have mucosal as well as skin disease.
- A- question for a nerve sheath myxoma is what stain is positive in this tumor?
A. EMA
B. S100
C. PAS
D. CD68
E. SMA
►B
Nerve sheath myxoma or myxoid neurothekeoma is S100 positive and EMA negative. It is a collection of stellate and pale spindle cells in a myxoid matrix.
367- A 40-year-old female presents for a scalp biopsy. On histology, you note premature desquamation of the inner root sheath, eccetricial epithelial atrophy with hair shafts in close proximity to the dermis, and concentric lamella fibroplasia of some follicles. There is variably dense lymphocytic perifollicular inflammation, primarily at the level of the upper isthmus and lower infundibulum. There is occasional fusion of the infundibula. Based on the findings of the scalp biopsy, what is the most likely diagnosis?
A. androgenetic alopecia
B. lichen planopilaris
C. telogen effluvium
D. central centrifugal cicatricial alopecia
E. trichotillomania
Correct choice: D. central centrifugal cicatricial alopecia
Explanation: On histology, central centrifugal cicatricial alopecia demonstrates premature desquamation of the inner root sheath, eccentric epithelial atrophy (thining) with hair shafts in close proximity to the dermis, and concentric lamellar fibroplasia of affected follicles. There is variably dense lymphocytic perifollicular inflammation, primarily at the level of the upper isthmus and lower infundibulum. There is occasional fusion of infundibula (polytrichia). In advanced lesions, total destruction of the follicular epithelium with retained hair shaft fragments and granulomatous inflammation are present.
- In trichotillomania, follicles are normal size, there is trichomalacia and pigment casts without significant inflammation. There is an increased number of terminal catagen or telogen hairs. There is incomplete disrupted follicular anatomy. The total number of hairs both terminal and vellus is normal.
- In androgenetic alopecia there is a normal total numbr of follicles and no significant inlfmamation, increased number and percentage of vellus hairs, numerous fibrous streamers, and slightly increased telogen count. Uninvolved scalp appears normal.
- Telogen effluvium demosntrates a normal total number of hairs, normal number of terminal (large) hairs, absence of inflammation and scarring. There is an increase in telogen count to > 20%.
- Lichen planopilaris demonstrates a band-like mononuclear cell infiltrate obscuring the interface between follicular epithelium and dermis; vacuolar alteration at the interface and hypergranulosis within affected infundibula is typical. Colloid or Civatte bodies are occasionally found as part of the itnerface alteration. Inflammation affects the upper portion of the follicle (infundibulum and isthmus) most severely. Occasionally, epidermal changes of lichen planus are found.
369- What is the most likely causative organism?
A. Blastomyces dermatitidis
B. Coccidioides immitis
C. Lacazia loboi
D. Fonsecaea pedrosoi
E. Sporothrix schenckii
Correct choice: D. Fonsecaea pedrosoi
Explanation: These biopsy findings (Medlar bodies/copper pennies/sclerotic bodies) are diagnostic of chromoblastomycosis (chromomycosis), which is most often due to infection with Fonsecaea pedrosoi.
370- What would this lesion show histologically?
A. Well formed tuberculoid granulomas in a linear pattern
B. Scattered comedo-like cysts
C. A proliferation of basaloid cells with small ducts
D. A grenz zone with a lot of inflammatory cells and globi
E. Acanthosis and neutrophilic infiltrate
Correct choice: A. Well formed tuberculoid granulomas in a linear pattern
Explanation: This is tuberculoid leprosy which shows well formed tuberculoid granulomas in a linear pattern on histology. They are linear because they follow nerves and destroy them. Lepromatous leprosy is characterized by a dense infiltrate of macrophages with few lymphocytes in the dermis and subcutaneous tissue with a grenz zone, Virchow cells and globi.
371- This lesion will stain positive for all of the following markers EXCEPT:
A. Synaptophysin
B. TTF-1
C. Chromogranin A
D. CK20
E. EMA
Correct choice: B. TTF-1
Explanation: This is a biopsy of merkel cell carcinoma (MCC). MCC can be difficult to distinguish from small cell lung cancer, but MCC characteristically stains negative for TTF-1 (thyroid transcription factor-1) whereas small cell lung cancer stains positive for TTF-1.
372- A 47-year-old female presents with a diffuse dermatosis with tiny pustules most prominent in the flexural surfaces. The pustules then resolve with superficial, serpiginous, fine desquamation. Biopsy is performed and results are seen here. What cell type is depicted here, in the superficial pustule?
A. Melanocyte
B. Neutrophil
C. Histiocyte
D. Eosinophil
E. Mast cell
Correct choice: B. Neutrophil
Explanation: The patient most likely has Sneddon-Wilkinson syndrome or subcorneal pustular dermatosis. The histopathology shows a superficial neutrophilic pustule.
373- Which of the following histologic bodies is typically found in this condition?
A. Russell bodies
B. Cowdry Type A bodies
C. Henderson-Patterson bodies
D. Cowdry Type B bodies
E. Guarnieri bodies
Correct choice: B. Cowdry Type A bodies
Explanation: The concurrent presence of vesicles, pustules, erosions, and crusts is indicative of primary varicella infection. Cowdry Type A inclusion bodies are seen in HSV and VZV infection, and are characterized as large eosinophilic intranuclear inclusions with surrounding clear halos in infected cells.
Guarnieri bodies are seen in smallpox, which clinically displays lesions at the same stage of development (contrast this with the various stages of lesion development seen in varicella). Cowdry Type B inclusion bodies are seen in polio. Henderson-Patterson bodies are seen in molluscum contagiosum, and Russell bodies are found in rhinoscleroma and granuloma inguinale.
374- The patient just returned from a sunny vacation with this eruption. What is your diagnosis
A. Acute cutaneous lupus
B. Porphyria cutanea tarda
C. Seborrheic dermatitis
D. Rosacea
E. Phototoxic eruption
Correct choice: E. Phototoxic eruption
Explanation: The epidermis is still a basket weave so this process happened acutely.
There is no lymphocytic infiltrate that would be expected in lupus. We are not on sebaceous skin as would be expected for seborrheic dermatitis and rosacea. Porphyria cutanea tarta results in a subepidermal split with festooning of the dermal papillae.
375- This is a genodermatosis. Which statement is INCORRECT?
A. Nikolsky’s sign can be positive.
B. Has a predilection for neck/ axillae, intertriginous areas
C. Superinfection with herpes simplex virus can occur in the genital region
D. The responsible gene is ATP2C1
E. The responsible gene encodes a Ca2+ pump located in the sarcoplasmic reticulum
Correct choice: E. The responsible gene encodes a Ca2+ pump located in the sarcoplasmic reticulum
Explanation: This biopsy reveals diffuse suprabasilar acantholysis with a “dilapidated brick wall” appearance, which is indicative of Hailey-Hailey disease (familial benign chronic pemphigus). The responsible gene encodes a Ca2+ pump located in the Golgi apparatus (as opposed to Darier’s disease, which is due to a mutation in the ATP2A2 gene, which encodes a Ca2+ pump in the endoplasmic reticulum). Hailey-Hailey disease is due to an autosomal dominant mutation in ATP2C1. It presents initially with flaccid vesicles on an erythematous base, with a predilection for the neck/ axillae & intertriginous areas. The vesicles rupture easily and this gives rise to macerated
or crusted erosions. Nikolsky’s sign can be positive, and superinfection with herpes simplex virus (usually HSV2) can occur in the genital region.
376- A 10-year-old girl undergoes a surgical excision of a circumscribed nodule on the face (shown in image). In some areas there are shards of keratinous debris and calcification. The origin of this following neoplasm is typified by which of the following?
A. Follicular neural network
B. Cornification of the inner root sheath
C. Follicular dermal papillae
D. Vellus hair follicles
E. Follicular matrical cornification
Correct choice: E. Follicular matrical cornification
Explanation: Pilomatricomas are benign neoplasms or cysts typified by follicular matrical cornification. They presents as a solitary skin-colored or bluish nodule and are more common in childhood and adolescence. Calcification and ossification can develop in late lesions. Histologically, an early pilomatricoma frequently presents as a cyst with central matrical cornification. Pink trichohyaline granules illustrate matrical cornification. The central anucleate cornified cells are called ghost or shadow cells. Pilomatricoma is typified by follicular matrical cornification. Its pink trichohyaline granules illustrate matrical cornification and are identifiable at the transition point.
