Dermatopathology #3 Flashcards
What’s the diagnosis? Note the follicular induction and collagen trapping at the periphery.
Dermatofibroma
What’s the diagnosis?
Dermatofibroma
In which condition do “collagen balls” often form?
Dermatofibromas
Will dermatofibromas be positive or negative for CD34? What about factor XIIIa?
Classically dermatofibromas will be CD34- and factor XIIIa+
*Note: these stains can help to distinguish them from DFSP.
In which conditions is factor XIIIa typically positive? List four conditions.
- Dermatofibromas
- Fibrous papules of the face
- Angiofibromas
- Acquired digital fibrokeratomas
What’s the diagnosis? Hint: this is a type of dermatofibroma.
Aneurysmal dermatofibroma
What’s the diagnosis? Hint: this is a type of dermatofibroma.
Fibrous histiocytoma
What condition are hemosiderin-laden Touton giant cells (rigned siderophages) pathognomonic for?
Dermatofibroma
True or false: “dermatofibroma with monster cells” is considered a type of dermatofibroma.
True
*Note: the “monster cells” comprise cells with large hyperchromatic atypical nuclei.
What’s the diagnosis? Note the pale blue nodules embedded in a more cellular background. Hint: this is composed of myofibroblasts.
Adult myofibroma
*Note: the pale blue myofibroblasts have a colour very similar to cartilage.
What’s the diagnosis?
Adult myofibroma
What’s the diagnosis? Note the spindle cells with an East-West orientation and the corkscrew appearance of some myofibroblasts.
Dermatomyofibroma
What’s the most likely diagnosis in this biopsy from a plaque-like tumor showing a proliferation of spindle cells and cells with corkscrew nuclei. Hint: at scanning magnification, the sparing of adnexal structures is more obvious.
Dermatomyofibroma
Could the diagnosis be dermatomyofibroma?
Yes; dermatomyofibromas typically contain very thick elastic fibers
True or false: corkscrew nuclei are typical of myofibroblastic proliferations.
True; this is a biopsy of a Dupuytren’s contracture
What’s the most likely diagnosis in this biopsy taken from the plantar fascia? Note the nodules of myofibroblasts.
Lederhose disease (basically Dupuytren’s contractures of the plantar fascia)
True or false: these corkscrew nuclei could come from Lederhose disease.
True
*Note: Lederhose disease is basically Dupuytren’s contractures of the plantar fascia.
True or false: this biopsy could represent infantile myofibromatosis.
True; all forms of myofibromatosis have a tendency to form thick “ropy” collagen bundles, and the myofibroblasts often run in fascicles
What’s the diagnosis?
Scar
What’s the diagnosis in this previously traumatized area?
Hypertrophic scar
The term “acrospiroma” encompasses a large family of sweat gland tumors. Name the four major diagnoses within this category.
- Poromas
- Hidradenomas
- Dermal duct tumors
- Hidroacanthoma simplex
*Note: acrospiromas have a tendency towards clear cell change. Cuticle-lined ducts are usually present.
What’s the diagnosis in this previously traumatized area?
Keloid
True or false: this could be consistent with an infantile digital fibroma.
True
*Note: there are characteristic inclusion bodies adjacent to the nuclei.
**Note: this have high recurrance rates after excision, although they are benign.
What’s the most likely diagnosis in this biopsy showing plump fibroblasts and osteoclast-like giant cells?
Giant cell tumor of the tendon sheath
What’s the most likely diagnosis in this large fibrous tumor from the scapular area? Note the elastin deposits throughout the tumor. Hint: these also commonly occur over the greater trochanter.
Elastofibroma dorsi
This is a biopsy of an elastofibroma dorsi. What stain has likely been used to highlight the elastic fibers?
Verhoeff-Van Gieson
What’s the most likely diagnosis?
Sclerotic fibroma
What’s the most likely diagnosis? Note the stellate nuclei that are reminiscent of radiation fibroblasts. There are no mitoses.
Pleomorphic fibroma
What’s the diagnosis?
Sclerosing perineurioma
Could the biopsy below represent a sclerosing perineurioma?
Yes
What are fibrous papules of the face called if there are many of them?
Angiofibromas
What’s the diagnosis? Note the concentric perivascular fibrosis and stellate stromal cells.
Anigofibroma (if solitary, fibrous papule of the face)
What’s the most likely diagnosis in this solitary papule from the face?
Fibrous papule of the face
What’s the diagnosis in this biopsy from the face?
Fibrous papule of the face
What’s the diganosis in this biopsy from an acral site?
Acquired digital fibrokeratoma
*Note: these are bascially “fibrous papules of the face” on the fingers.
What’s the diagnosis in this biopsy showing RBC extravasation, “tissue culture” fibroblasts, and a loose myxoid pattern.
Nodular fasciitis
What is the condition characterized by “tissue culture” fibroblasts (i.e. stellate fibroblasts)?
Nodular fasciitis
What’s the diagnosis in this biopsy showing RBC extravasation and a loose myxoid pattern?
Nodular fasciitis
*Note: there are “tissue culture fibroblasts” seen.
What’s the diagnosis?
Nodular fasciitis
What’s the diagnosis in this biopsy from the distal extremity of a child or adolescent?
Calcifying aponeurotic fibroma
What’s the diagnosis in this biopsy from a child’s hand?
Calcifying aponeurotic fibroma
True or false: calcifying aponeurotic fibromas can sometimes have focal collections of osteoclast-like giant cells.
True
What’s the diagnosis in this biopsy from the abdominal wall? Note the myofibroblastic proliferation.
Desmoid tumor
What’s the diagnosis in this deeply invading tumor with a storiform pattern?
Dermatofibrosarcoma protuberans
*Note: any hypercellular tumor should be suspicious for a sarcoma.
What’s the diagnosis?
Dermatofibrosarcoma protuberans
What’s the diagnosis in this tumor that invades into the fat?
Dermatofibrosarcoma protuberans
*Note: there’s a storiform pattern, just like in a dermatofibroma.
What’s the eponymn associated with this pigmented variety of DFSP?
Bednar tumor
What’s the diagnosis in this densely cellular tumor?
Fibrosarcoma
What’s the diagnosis in this biopsy that shows a herringbone pattern?
Fibrosarcoma
Could the biopsy below represent a fibrosarcoma?
Yes; mitoses can be seen, although cytologic atypia tends to be more rare
What’s the diagnosis in this biopsy from sun-exposed skin?
Pleomorphic atypical fibroxanthoma (AFX)
*Note: AFX can also be spindled.
**Note: AFX is thought to be a low-grade sarcoma, or maybe even a SCC that is so poorly differentiated that the cells no longer express keratin.
Use the SLAM eponymn to come up with a differential diagnosis for a spindle-cell tumor that’s “slammed” up against the epidermis.
- Squamous cell carcinoma
- Leiomyosarcoma
- Atypical fibroxanthoma
- Melanoma (spindle cell)
*Note: this particular biopsy is a spindled atypical fibroxanthoma.
This biopsy is often misdiagnosed as involving palisading granulomas, especially at scanning magnification. This tumor will stain for both keratin and vimentin.
Epithelioid sarcoma
What’s the diagnosis in this tumor that stains for both keratin and vimentin? Note the biphasic popluation of cells. Hint: this tumor is often misdiagnosed as a pallisaded granuloma, especially at scanning magnification.
Epithelioid sarcoma
What stain was most likely used?
Trichome stain
This is an elastofibroma dorsi. What stain was most likely used to stain the abnormal elastic fibers?
Verhoeff-Van Gieson
What’s the drawback of using a Giemsa stain to highlight mast cells?
The mast cells won’t stain if they’ve degranulated
What’s the name of the mast cell stain that doesn’t rely on the presence of granules (i.e. if the mast cells have degranulated)?
Leder stain
Other than mast cells, what cells will stain positively with a Leder stain?
Myeloid cells (e.g. leukemia cutis)
What stain was most likely used here? Other than to highlight a basement membrane, when might this stain be used?
- Periodic acid Schiff (PAS) stain
- To highlight fungi, especially in the stratum corneum
*Note: this is a PAS stain with a light green counter-stain, highlighting fungi within the stratum corneum.
What stain has most likely been used to stain this biopsy showing focal mucinosis? List three other stains that could also be used to highlight mucin.
- Colloidal iron
- Alcian blue, toluidine blue, and mucicarmine can also be used
What stain was most likely used here to highlight the mucinous capsule of crytopoccocus?
Mucicarmine
What stain was most likely used to highlight the amyloid in this biopsy?
Congo red
*Note: with a Congo red stain, amyloid will stain a brick red colour, but will display an apple-green birefringence with polarized light
List three stains that can be used to highlight amyloid.
- Congo red
- Thioflavin T (requires a fluorescent microscope)
- Crystal violet
*Note: the image shows amyloid stained with thioflavin T, examined under a fluorescent microscope.
What stain was most likely used here?
Perls prussian blue, because the Monsel’s solution (which contains iron and if occasionally used to achieve hemostasis) is highlighted, while the melanin is not
What stain can be used to higlight melanin?
Fontana-Masson stain
Which two stains can be used to highlight calcium?
- Von Kossa (stains black)
- Alizarin red (stains orange-red)
What colour do Gram + organisms stain on Gram stain? Gram - organisms?
- Gram + stain black
- Gram - stain red
List the stain most commonly used to highlight bacteria within tissue (i.e. not on the surface of the skin).
Brown-Hopps or Brown-Brenn method
What stain was most likely used to highlight these fungi?
Periodic acid Schiff (PAS) stain
What’s the name of the silver stain that was used to highlight these fungi?
Grocott’s methenamine silver stain
List two stains that can be used to highlight acid-fast bacilli.
Fite stain and Ziehl-Neelsen stain
Why won’t Norcardia bacteria stain with a Ziehl-Neelson stain?
Because it’s only partially acid-fast; because of this, Fite stains are more commonly used in skin biopsies to look for all AFBs
List three silver stains that can be used to highlight spirochetes.
- Warthin-Starry
- Dieterle
- Steiner (modified Dieterle)
This stain comprises a cocktail of high and low molecular weight monoclonal cytokeratin antibodies. It will stain all epithelial tumors.
AE1/AE3
This stain will highlight muscle that originates from vascular smooth muscle.
Vimentin
*Note: desmin is the other smooth muscle stain, but if the muscle originates from vascular smooth muscle, it won’t stain.
CD34 can be used to help diagnose DFSP (see below), but it also highlights vascular endothelium. If a biopsy of morphea is stained with CD34, what does it show?
Dramatic decrease in CD34 staining
*Note: this is a useful marker early on, when the signs of morphea are not obvious on H&E.
True or false: CD3 is a pan-T marker.
True
What’s the diagnosis in this biopsy that shows mature fat?
Lipoma
What’s the diagnosis in this biopsy that shows mature fat cells and septae with many blood vessels?
Angiolipoma
*Note: many thromboses are often present within the small vessels.
What’s the diagnosis in this biopsy that shows a well-circumscribed tumor with mature fat cells, interspersed with zones of bland spindle cells?
Spindle cell lipoma
What’s the diagnosis in this biopsy showing fully mature spindle cells and mature collagen?
Fibrolipoma (a fully mature spindle cell lipoma)
What’s the diagnosis in this well-circumscribed tumor of lipocytes containing multinucleated floret cells with overlapping nuclei?
Pleomorphic lipoma
*Note: the multinucleate floret cells have overlapping nuclei arranged at the periphery like the petals of a flower.
What’s the diagnosis in this biopsy that shows mature fat and smooth muscle radiating in a pinwheel fashion from the walls of muscular vessels?
Angiomyolipoma
*Note: the smooth muscle is related to large muscular vessels within the lesion.
What’s the diagnosis in this biopsy showing “mulberry” lipocytes, similar to the brown fat seen in hibernating animals?
Hibernoma
What’s the diagnosis in this biopsy showing mature fat that has replaced much of the dermis?
Nevus lipomatosis superficialis of Hoffmann and Zurhelle
What’s the diagnosis?
Piloleiomyoma
*Note: there are interlacing bundles of smooth-muscle fibers resembling arrector pili muscle “on steroids”.
What type of tissue is most likely involved here?
Muscle tissue
*Note: there are perinuclear vacuoles that actually represent glycogen accumulations (“glycogen snacks”).
What’s the most likely diagnosis in this biopsy that looks like a “marble composed of muscle”?
Angioleiomyoma
*Note: slit-like vascular spaces may be present.
What’s the most likely diagnosis in this biopsy showing high cellularity, mitoses, and nuclear atypia?
Leiomyosarcoma
*Note: these lesions occur most commonly on the extensor surfaces of middle-aged men.
What’s the most likely diagnosis?
Leiomyosarcoma
What’s the diagnosis?
Osteoma cutis
What’s the diagnosis?
Neurofibroma
What’s the diagnosis in this biopsy that shows large fascicles of neurofibroma surrounded by perineurium?
Plexiform neurofibroma
*Note: the background comprises diffuse neurofibroma.
What’s the diagnosis?
Schwannoma
*Note: Antoni B tissue is loose edematous degeneration of Antoni A tissue.
What’s the other term for schwannoma?
Neurilemmoma
What’s the diagnosis?
Schwanomma
*Note: verocay bodies are seen within Antoni A tissue.
What’s the diagnosis in this entity characteristic of Carney complex?
Psammomatous melanotic schwannoma (a variant of schwanomma that contains psammoma bodies and melanin)
Could this biopsy represent an ancient schwannoma?
Yes; no mitoses are present, and the biopsy resembles a benign schwannoma with hyperchromatic pleomorphic nuclei
The biopsy below represents an ancient schwannoma. What is the malignant counterpart for this entity?
Malignant peripheral nerve sheath tumor (will have mitotic figures and an expansive growth pattern)
What’s the diagnosis in this recently traumatized tissue?
Traumatic neuroma
What’s the diagnosis?
Palisaded encapsulated neuroma
*Note: the name is a misnomer, as there is usually no palisading and only an inconspicuous capsule.
What’s the diagnosis in this congenital papule located on the lateral aspect of the hand?
Supernumerary digit (rudimentary polydactyly)
What’s the diagnosis?
Supernumerary digit (rudimentary polydactyly)
What’s the diagnosis in this tumor that stains positively for S100?
Granular cell tumor
*Note: sheets of large polygonal cells with abundant granular cytoplasm is typical. Giant lysosomal granules are a characteristic finding.
What’s the diagnosis?
Granular cell tumor
What’s the diagnosis in this CK20 positive tumor?
Merkle cell carcinoma
Use the “LEMONS” mnemonic to provide a differential diagnosis for “small blue cell” tumors.
“LEMONS”
- Lymphoma
- Ewing’s sarcoma
- Merkle cell carcinoma/melanoma
- Oat cell carcinoma of the lung
- Neuroblastoma
- Small cell endocrine carcinoma
What are the two types of neurothekeomas?
- Myxoid neurothekeoma
- Cellular neurothekeoma
What’s the diagnosis in this S100 positive tumor?
Myxoid neurothekeoma
*The other type of neurothekeoma is a cellular neurothekeoma.
**These most commonly occur on the head and neck of young and middle-aged females.
Will myxoid neurothekeomas stain positively for colloidal iron?
Yes! They’re “myxoid” (i.e. contain mucin)!
What’s the diagnosis?
Angiokeratoma
What’s the diagnosis?
Lymphangioma
*Note: lymph may appear amorphous, string, and/or granular.
What’s the diagnosis in this biopsy that shows dilation of dermal blood vessels but no proliferation? Hint: this lesion appeared as a progressive vascular lesion on a woman’s leg.
Anigoma serpiginosum
*Note: this is considered a capillary malformation.
True or false: this could represent nevus flammeus?
True
*Note: nevus flameus is due to dilated capillaries (it’s a capillary malformation).
What’s the diagnosis?
Venous lake
What’s the diagnosis in this biopsy that shows glomus cells like “strings of black pearls”?
Glomus tumor
*Note: these are commonly tender.
What’s the diagnosis in this biopsy that shows mostly prominent vessels, but also two layers of glomus cells around these vessels?
Glomangioma
*Note: one or two layers of glomus cells can be found around these prominent blood vessels.
What’s the diagnosis?
Glomangioma
*Note: there can be prominent or inconspicuous amounts of small muscle. Here, there is a substantial amount.
What’s the diagnosis in this biopsy that shows endothelial cells and ectatic vessels?
Pyogenic granuloma
*Note: well-defined fibrous septae should be seen.
What’s the diagnosis?
Pyogenic granuloma
What’s the diagnosis in this biopsy that looks like a pyogenic granuloma, but isn’t distinctly lobular?
Bacillary angiomatosis
*Note: the vessels are round and capillary-sized.
What’s the diagnosis in this pyogenic-granuloma-like papule showing amorphic collections of organisms?
Bacillary angiomatosis
What’s the diagnosis?
Cherry angioma
*Note: the vessels are distinctly hyalinized.
What’s the diagnosis in this biopsy from a child showing solidly packed endothelial cells, all GLUT-1 positive?
Infantile hemangioma
What’s the diagnosis in this pigmented lesion?
Targetoid hemosiderotic hemangioma
*Note: these lesions probably represent trauma to pre-existing hemangiomas.
What’s the diagnosis in this biopsy that shows superficially dilated vessel and vascular proliferation that surrounds pre-existing vessels? Hint: this lesion can mimic angiosarcoma and kaposi’s sarcoma.
Targetoid hemosiderotic hemangioma
*Note: these lesions probably occur as a result of trauma to pre-existing hemangiomas.
**Note: hemosiderin is often found, particularly at the periphery of the lesion.
What’s the diagnosis in this biopsy that shows superficially dilated blood vessels and peripheral hemosiderin deposition?
Targetoid hemosiderotic hemangioma
*Note: these lesions can sometimes mimic angiosarcoma and kaposi’s sarcoma, due to the tendency for vascular proliferation surrounding pre-existing vessels.
What’s the diagnosis in this biopsy from a tender lesion? Hint: these lesions sometimes demonstrate hyperhidrosis.
Eccrine angiomatous hamartoma
*Note: these lesions can be tender, or even spontaneously painful, but they don’t have to be.
What’s the diagnosis in this biopsy showing equal parts capillaries and eccrine glands?
Eccrine angiomatous hamartoma
*Note: these lesions can occasionally demonstrate hyperhidrosis.
What’s the diagnosis?
Glomeruloid hemangioma
*Note: these lesions are associated with POEMS syndrome and Castleman’s disease.
What does POEMS syndrome stand for?
- Polyneuropathy
- Organomegaly
- Endocrinopathy
- M protein
- Skin changes
List two diseases associated with glomeruloid hemangioma.
- POEMS syndrome
- Castleman’s disease
What’s the diagnosis in this lesion showing an increased number of blood vessles with small lumens?
Microvenular hemangioma
What’s the diagnosis?
Tufted angioma (angioblastoma)
*May be associated with Kasabach–Merritt syndrome in congenital cases, but it usually presents as an acquired lesion in children and young adults.
**Kaposiform hemangioendotheliomas are the other tumors associated with Kasabach-Merritt.
What’s the other name for tufted angioma?
Angioblastoma
What’s the diagnosis in this biopsy showing stag-horn ectatic vessels and a curlicue pattern of spindle cells on higher magnification?
Hemangiopericytoma
What’s the diagnosis in this biopsy showing endothelial-lined vessels surrounded by a proliferation of pericytes? Hint: in some areas a curlicue pattern of spindle cells is seen.
Hemangiopericytoma
What’s the diagnosis in this biopsy showing solid areas of spindle cells at higher magnification? Hint: at this magnification, the lesion resembles “hemorrhagic lung”.
Spindle cell hemangioendothelioma
*Note: these lesions are benign, and probably represent a response to vascular trauma.
Can phleboliths form within spindle cell hemangioendotheliomas?
Yes
*Note: at scanning magnification this biopsy has the appearance of “hemorrhagic lung” with blood filled “alveolar spaces”.
What’s the diagnosis in this vascular lesion that represents a low-grade angiosarcoma? Note the large epithelioid cells and the presence of characteristic intracellular lumens.
Epithelioid hemangioendothelioma (a low-angiosarcoma with intermediate malignant potential)
*Skin involvement is uncommon and is usually associated with more deeply seated disease, often associated with a vein.
**30% develop metastases in regional lymph nodes, lung, liver or bone, but less than 50% of patients with metastases die of their disease.
What’s the diagnosis in this lesion that represents a form of low-grade angiosarcoma?
Retiform hemangioendothelioma (also known as hobnail hemangioendothelioma, which is not to be confused with hobnail hemangioma)
*Note: this tumor occurs most commonly on the extremities of young adults.
**Note: HHV-8 has been associated with this tumor.
What is the most common location for this vascular tumor?
Retiform hemangioendotheliomas occur most commonly on the extremities of young adults
What’s the diagnosis in this biopsy from a bruise-like lesion from the scalp of an elderly person?
Angiosarcoma
What’s the diagnosis?
Angiosarcoma
What’s the name of the syndrome where angiosarcoma occurs in the context of chronic lymphedema?
Stuart-Treves syndrome
List four endothelial markers.
- Factor VIII (unreliable)
- CD34 (not specific)
- CD31 (very specific, but background staining common)
- Ulex europeus lectin (clean staining)
What’s the diagnosis in this sometimes difficult-to-diagnose-early-on tumor? Hint: the presence of plasma cells is helpful.
Early patch-stage Kaposi’s sarcoma
*Note: this early tumor is characterized by bizarre stag-horn ectatic lymphatic-like vessels and plasma cells.
What’s the diagnosis?
Kaposi’s sarcoma
What’s the promentory sign? What disease is it associated with?
- When an old vessel juts into a new vascular space, giving the appearance of a vessel “floating in space”
- Kaposi’s sarcoma
What’s the diagnosis in this biopsy showing a “busy dermis” surrounding adnexal structures and pre-existing vessels?
Plaque Kaposi’s sarcoma
*Note: the promentory sign may be present.
What’s the diagnosis in this biopsy showing mitoses and hemosiderin deposition?
Kaposi’s sarcoma
What’s the diagnosis?
Kaposi’s sarcoma
*Note: within the nodule, RBCs are seen lining up between the spindle cells.
