109: Appendage Tumors Flashcards
What are the classifications of cutaneous appendage tumors?
Cutaneous appendage tumors are classified into four main types: Eccrine, Apocrine, Follicular, and Sebaceous.
What is the clinical presentation of cutaneous appendage tumors?
The clinical presentation typically includes solitary or multiple dermal papules or nodules, epidermal changes, skin-colored, pink, or bluish hue, possible visibility of hair follicle orifice or central punctum, specific site or age predilections, and diagnosis usually requires biopsy and subsequent histopathology.
What are the histopathologic diagnosis aims for appendage tumors?
The aims include arriving at a specific diagnosis, distinguishing benign from malignant tumors, determining whether the tumor is low or high grade, and identifying tumors associated with genetic syndromes.
What are the management strategies for benign and malignant appendage tumors?
Management strategies include monitoring clinically, surgical excision, and ablative therapies for benign tumors; and surgical excision using conventional or Mohs micrographic techniques for malignant tumors.
What are the characteristics of normal eccrine glands?
Normal eccrine glands are found throughout the body, especially on palms and soles, composed of a secretory coil and a duct connecting to the epidermis.
What are the common clinical features of benign hidradenoma?
Commonly occurs in the fifth decade of life, affects both genders, can occur at all anatomic sites, typically presents as a solitary dermal nodule, color ranges from flesh-colored to red or bluish, and size ranges between 0.5 and 10.5 cm.
What is the etiology and pathogenesis of benign hidradenoma?
50% carry t(11;19) translocation resulting in a fusion between the MECT1 gene and the MAML2 gene, promoting tumorigenesis by inducing cAMP/CREB target genes.
What are the histopathological features of poroma?
Relatively well-circumscribed endophytic proliferations of cuboidal cells with basophilic round nuclei and eosinophilic cytoplasm, with ductal differentiation variably present.
What are the differential diagnoses for hidradenoma?
Differential diagnoses include squamous cell carcinoma, invasive adenocarcinoma, and metastatic renal cell carcinoma.
What is the management strategy for benign hidradenoma?
Complete excision with clear margins is recommended, with local recurrence about 10% if not completely excised.
What are the clinical features of poroma?
Typically affects middle-aged to elderly patients, presents as a single flesh-colored to red papule or nodule, and can appear on acral surfaces.
What is the likely diagnosis for a solitary dermal nodule on the head and neck region with ductal differentiation?
The likely diagnosis is benign hidradenoma, also known as nodular hidradenoma or eccrine acrospiroma.
What genetic translocation is associated with 50% of benign hidradenomas?
The t(11;19) translocation resulting in a fusion between the MECT1 gene and the MAML2 gene.
What is the diagnosis for a single, flesh-colored to red papule on the acral surface with ductal differentiation?
The diagnosis is poroma, a benign eccrine neoplasm.
What are the four subtypes of poroma?
The four subtypes are poroma, hidroacanthoma simplex, dermal duct tumor, and poroid hidradenoma.
What are the clinical features of cylindroma?
Cylindromas present as smooth, flesh-colored to red nodules, primarily in the head and neck region, and occur in adults with a female predilection.
What is the etiology and pathogenesis of cylindromas?
Cylindromas associated with Brooke-Spiegler syndrome are caused by mutations in the CYLD tumor-suppressor gene.
What is the histopathological characteristic of cylindromas?
Cylindromas are characterized by islands of basaloid cells arranged in a ‘jigsaw puzzle’ pattern, surrounded by eosinophilic basement membrane material.
What is the management strategy for cylindromas?
The treatment of choice is surgical excision with clear margins.
What are the clinical features of spiradenoma?
Spiradenomas typically present as single, pink, gray, or blue dermal nodules on the trunk, primarily affecting young to middle-aged adults.
What is the histopathological feature of spiradenomas?
Spiradenomas are multinodular, unencapsulated dermal neoplasms composed of basaloid cells arranged in cords in a trabecular pattern.
What is the management approach for spiradenomas?
The management typically involves surgical excision with clear margins.
What are the clinical features of syringomas?
Syringomas present as multiple, 1- to 3-mm, flesh-colored or yellow papules, primarily on the face.
What is the histopathological characteristic of syringomas?
Syringomas are well-circumscribed and composed of epithelial cells arranged in cords, nests, and small ductal structures.
What is the management strategy for syringomas?
Management focuses on cosmetic treatment using destructive methods, although they may have adverse side effects.
What is the diagnosis for multiple smooth, flesh-colored nodules on the head and neck with a ‘jigsaw puzzle’ arrangement?
The diagnosis is cylindroma.
What gene mutation is associated with multiple cylindromas in Brooke-Spiegler syndrome?
Mutations in the CYLD tumor-suppressor gene at chromosome 16q.
What is the diagnosis for a single, pink dermal nodule on the trunk with multinodular basaloid cells?
The diagnosis is spiradenoma.
What histopathological features distinguish spiradenoma from other tumors?
Spiradenoma is characterized by multinodular basaloid cells arranged in a trabecular pattern and scattered lymphocytes.
What is the diagnosis for multiple flesh-colored papules on the face with ‘tadpole’-shaped ductal structures?
The diagnosis is syringoma.
What syndrome is associated with multiple syringomas?
Down syndrome.
What are the clinical features of malignant hidradenocarcinoma?
Malignant hidradenocarcinoma is a rare adnexal neoplasm, typically presenting as a solitary mass averaging 2 to 2.5 cm.
What histopathological features distinguish hidradenocarcinoma from atypical hidradenoma?
Distinguishing features include deep extension, large areas of comedo necrosis, infiltrative growth, and nuclear pleomorphism.
What is the management strategy for metastatic hidradenocarcinoma?
Management includes wide local excision and chemotherapy for metastatic cases.
What are the key differential diagnoses for porocarcinoma?
Differential diagnoses include squamous cell carcinoma, with immunohistochemical markers aiding in differentiation.
What are the clinical features of porocarcinoma?
Porocarcinoma typically affects adults in their sixth and seventh decades, presenting as nodular or verrucous growth.
What histopathological characteristics are associated with cylindromas and spiradenomas?
Features include high mitotic rate, nuclear pleomorphism, and infiltrative growth patterns.
What is the diagnosis for a solitary mass on the head and neck with malignant cytomorphology?
The diagnosis is malignant hidradenocarcinoma.
What histopathological features distinguish malignant hidradenocarcinoma from atypical hidradenoma?
Malignant hidradenocarcinoma is distinguished by deep extension, comedo necrosis, and nuclear pleomorphism.
What is the diagnosis for a nodular growth on the lower extremity with malignant basaloid epithelial cells?
The diagnosis is porocarcinoma.
What immunohistochemical markers can help differentiate porocarcinoma from squamous cell carcinoma?
Markers include EMA, CEA, cytokeratin 19 (CK19), and CD117 (cKIT).
What is the diagnosis for a rapidly growing nodule on the head with malignant features?
The diagnosis is cylindrocarcinoma or spiradenocarcinoma.
What are the four main patterns seen in cylindrospiradenocarcinomas?
- Salivary gland–type basal cell adenocarcinoma-like pattern, low grade. 2. Salivary gland–type basal cell adenocarcinoma-like pattern, high grade. 3. Invasive adenocarcinoma, not otherwise specified. 4. Sarcomatoid carcinoma.
What is the clinical course and prognosis for patients with cylindrospiradenocarcinomas?
Cylindrospiradenocarcinomas can metastasize, with poor prognosis associated with high-grade morphology.
What are the histopathological features of Digital Papillary Adenocarcinoma?
Multinodular, poorly circumscribed dermal tumor with solid and cystic areas and papillary projections.
What is the clinical course and prognosis for patients with cylindrospiradenocarcinomas?
- Metastasize
- Associated deaths reported
- Poor prognosis associated with high-grade morphology and Brooke-Spiegler syndrome leading to malignant transformation.
What are the histopathological features of Digital Papillary Adenocarcinoma?
- Multinodular, poorly circumscribed dermal tumor
- Extension into the subcutis is not uncommon
- Solid and cystic areas with papillary projections
- Papillary structures include true papillae with fibrovascular cores and pseudo-papillary structures without fibrovascular cores.
What are the differential diagnoses for Digital Papillary Adenocarcinoma?
- Cyst
- Giant cell tumor
- Vascular tumor
- Histological differential diagnosis includes hidradenoma, tubular adenoma, and metastatic disease from thyroid, breast, and GI primaries.
What is the management strategy for Digital Papillary Adenocarcinoma?
- Wide excision
- Digital amputation of the primary lesion
- Close clinical follow-up as metastases have been reported up to 20 years following initial presentation.
What are the clinical features of Microcystic Adnexal Carcinoma?
- Rare malignant adnexal tumor
- Affects adult patients over a wide age range
- Equal sex distribution
- Firm, indurated plaque typically found on the central face, classically in perioral or periocular areas.
What are the histopathological characteristics of Microcystic Adnexal Carcinoma?
- Infiltrative growth pattern with frequent extension beyond the dermis into subcutaneous tissues
- Composed of strands, cords, and cysts of epithelial tumor cells embedded in a sclerotic stroma
- Perineural invasion is frequent and tumor cells stain for cytokeratins.
What is the clinical course and prognosis for Microcystic Adnexal Carcinoma?
- Slow-growing tumor
- Locally aggressive with significant morbidity due to frequent perineural involvement
- Metastatic disease is exceedingly rare.
What are the management options for Microcystic Adnexal Carcinoma?
- Surgical excision - Mohs micrographic surgery has lower recurrence rates than conventional surgical techniques
- Radiation therapy - not recommended as first-line but can be considered in poor surgical candidates
- Chemotherapy - no role
- Recurrent disease in the periocular area may benefit from review of paraffin sections to detect residual, small tumor foci.
What are the four main histopathological patterns seen in cylindrospiradenocarcinomas?
The four main patterns are: (1) salivary gland–type basal cell adenocarcinoma–like pattern (low grade), (2) salivary gland–type basal cell adenocarcinoma–like pattern (high grade), (3) invasive adenocarcinoma (not otherwise specified), and (4) sarcomatoid carcinoma.
A middle-aged male presents with a slow-growing mass on the distal aspect of a finger. Histopathology shows multinodular dermal tumor with papillary projections. What is the diagnosis?
The diagnosis is digital papillary adenocarcinoma.
What is the most common site of metastasis for digital papillary adenocarcinoma?
The most common site of metastasis for digital papillary adenocarcinoma is the lung.
A patient presents with a firm, indurated plaque on the central face. Histopathology shows infiltrative growth with strands and cords of epithelial tumor cells in a sclerotic stroma. What is the diagnosis?
The diagnosis is microcystic adnexal carcinoma, a rare malignant adnexal tumor.
What is the preferred surgical technique for microcystic adnexal carcinoma?
Mohs micrographic surgery is the preferred surgical technique for microcystic adnexal carcinoma due to its lower recurrence rates.
A patient presents with a slow-growing, firm plaque on the central face. Histopathology shows infiltrative growth with perineural invasion. What is the diagnosis?
The diagnosis is microcystic adnexal carcinoma.
What is the clinical significance of perineural invasion in microcystic adnexal carcinoma?
Perineural invasion in microcystic adnexal carcinoma is associated with significant morbidity due to its locally aggressive nature.
A middle-aged male presents with a slow-growing mass on the finger. Histopathology shows papillary projections with true and pseudo-papillae. What is the diagnosis?
The diagnosis is digital papillary adenocarcinoma.
What is the recommended management for digital papillary adenocarcinoma?
Wide excision or digital amputation of the primary lesion is the recommended management for digital papillary adenocarcinoma.
What are the characteristics of tumors with apocrine differentiation?
Tumors with apocrine differentiation are composed of cells that show decapitation secretion. They develop in association with normal apocrine glands, which are found in the axillary, groin, and perineal regions. These tumors typically have a secretory coil located in the deep dermis or subcutis, lined by cuboidal epithelium with intracytoplasmic zymogen granules and characteristic apical ‘snouting’. Luminal cells are surrounded by myoepithelial cells.
What is the clinical presentation of hidrocystoma?
Hidrocystoma presents as a tan to bluish-black, translucent papule, often located in the periorbital area of the face. It can also appear in other locations such as the axilla and groin. Adults of middle age are primarily affected, with a slight predilection for females. Multiple lesions may occur in some cases.
What are the differential diagnoses for hidrocystoma?
The differential diagnoses for hidrocystoma include:
- Epidermoid cyst
- Basal cell carcinoma
- Melanoma (depending on the color of the lesion)
- Dacryops - a cyst of the lacrimal gland, distinguished by the presence of lacrimal gland tissue.
What are the management strategies for multiple hidrocystomas?
Management strategies for multiple hidrocystomas include:
- Botulinum toxin
- Electrodessication and curettage
- Laser treatment
- Topical atropine
These treatments focus on cosmetic improvement, as multiple hidrocystomas can be more difficult to treat compared to solitary lesions, which can be surgically excised or punctured.
What are the histopathological features of apocrine mixed tumors?
- Unencapsulated, multinodular dermal neoplasms with frequent infiltration into surrounding tissue.
- Composed of epithelial, myoepithelial, and stromal elements in varying amounts.
- Glandular epithelium with decapitation secretion, absent in the eccrine variant.
- Follicular and sebaceous differentiation observed.
- Immunohistochemistry highlights cellular components, with epithelial ductal structures staining positively for cytokeratins and EMA.
A middle-aged female presents with a tan, translucent papule in the periorbital area. Histopathology shows bilayered epithelium with decapitation secretion. What is the diagnosis?
The diagnosis is benign hidrocystoma, which can be of apocrine or eccrine origin.
What syndromes are associated with multiple hidrocystomas?
Multiple hidrocystomas are associated with Schöpf-Schulz-Passarge syndrome and Goltz-Gorlin syndrome.
A middle-aged male presents with a firm, flesh-colored nodule on the head. Histopathology shows a multinodular dermal neoplasm with epithelial, myoepithelial, and stromal elements. What is the diagnosis?
The diagnosis is apocrine mixed tumor, also known as chondroid syringoma.
What gene rearrangement is associated with apocrine mixed tumors?
PLAG1 gene rearrangements are associated with apocrine mixed tumors.
A patient presents with a solitary, flesh-colored nodule on the head. Histopathology shows multinodular dermal neoplasm with epithelial and stromal elements. What is the diagnosis?
The diagnosis is apocrine mixed tumor.
What is the clinical course of apocrine mixed tumors?
Apocrine mixed tumors are benign with an indolent clinical course, and malignant transformation is extremely rare.
What are the clinical features of syringocystadenoma papilliferum?
- Rare, benign neoplasm
- Typically occurs in children and young adults
- Appears as a single, brown to red plaque on the scalp, resembling a wart
- May have serosanguinous drainage and ulceration
- Can present as small papules in association with nevus sebaceous
- Rarely found on trunk and extremities.
What histopathological features are characteristic of tubular adenoma?
- Well-circumscribed, unencapsulated dermal nodule composed of tubules in fibrotic stroma
- Epithelium lining consists of single to multiple layers of cuboidal cells with an outer layer of myoepithelial cells
- Luminal cells stain for cytokeratins (CK7, CEA, EMA)
- Myoepithelial markers (calponin, p63, smooth muscle actin) present
- Complex architecture within the tubules, including micropapillae and cribriforming.
What is the management strategy for syringocystadenocarcinoma papilliferum?
- Surgical excision is recommended, even though malignant transformation is rare.
- Treatment can be performed using:
- Conventional surgical methods
- Mohs micrographic techniques.
What are the clinical features of hidradenoma papilliferum?
- Typically found in the anogenital region of females, particularly the vulva
- Appears as a flesh-colored to red nodule, often less than 1 cm in size.
What are the differential diagnosis considerations for tubular adenoma?
- Tubular adenoma may have overlapping histological features with syringocystadenoma papilliferum.
- Important to differentiate based on specific histopathological characteristics and clinical presentation.
A child presents with a single, brown plaque on the scalp with serosanguinous drainage. Histopathology shows invagination of papillations with fibrous cores containing plasma cells. What is the diagnosis?
The diagnosis is syringocystadenoma papilliferum, a rare benign neoplasm.
What mutations are associated with syringocystadenoma papilliferum?
Mutations in BRAF (V600E), NRAS, and HRAS are associated with syringocystadenoma papilliferum.
A middle-aged patient presents with a single, flesh-colored nodule on the scalp. Histopathology shows well-circumscribed tubules embedded in a fibrotic stroma. What is the diagnosis?
The diagnosis is tubular adenoma, a rare benign appendage neoplasm.
What immunohistochemical markers are used to identify tubular adenomas?
Immunohistochemical markers such as CK7, CEA, EMA, calponin, p63, and smooth muscle actin are used to identify tubular adenomas.
A female patient presents with a flesh-colored nodule on the vulva. Histopathology shows a solid-cystic dermal nodule with decapitation secretion. What is the diagnosis?
The diagnosis is hidradenoma papilliferum, an adenoma of the mammary-like anogenital glands.
What mutations are associated with hidradenoma papilliferum?
Activating mutations in PIK3CA are associated with hidradenoma papilliferum.
A patient presents with a single, red plaque on the scalp with a wart-like appearance. Histopathology shows epithelial cells with decapitation secretion and fibrous cores containing plasma cells. What is the diagnosis?
The diagnosis is syringocystadenoma papilliferum.
What is the management approach for syringocystadenoma papilliferum?
Surgical excision is the recommended management approach for syringocystadenoma papilliferum.
What are the histopathological features of nipple adenoma?
- Endophytic, well-circumscribed proliferation of glandular structures.
- Glands or tubules lined by a bilayered epithelium:
- Inner (luminal) apocrine secretory epithelium
- Outer myoepithelial layer
- Presence of solid, papillary, and cystic areas.
- Sclerosis with irregular border or infiltration.
- Possible epidermal erosion or ulceration with an associated inflammatory infiltrate.
- Focal necrosis is noted, but not florid.
What is the management strategy for nipple adenoma?
The management strategy for nipple adenoma includes:
- Surgical excision - this is the treatment of choice.
- Monitoring for recurrence, as it can occur following incomplete excision.
What are the clinical features associated with nipple adenoma?
- Occurs primarily in females in their fourth and fifth decades.
- Presentation may be unilateral with serous or bloody nipple discharge.
- Possible crusting or ulceration of the nipple.
- May present as a dermal nodule in some cases.
What differential diagnoses should be considered for nipple adenoma?
- Paget disease
- Mammary ductal carcinoma - focal necrosis, with cytological atypia absent in nipple adenoma.
- Eczema
- Invasive carcinoma - to be ruled in due to sclerosis, but ruled out due to lack of atypia.
- Nipple adenoma is confirmed by the presence of myoepithelial cells (verified through immunohistochemistry).
What is the clinical course and prognosis for nipple adenoma?
The clinical course and prognosis for nipple adenoma are generally benign, with the following points:
- Although it is a benign proliferation, coincidental mammary carcinoma has been reported.
- Surgical excision is effective, but recurrence can occur following incomplete excision.
A female in her fourth decade presents with unilateral serous nipple discharge. Histopathology shows a well-circumscribed proliferation of glandular structures with a bilayered epithelium. What is the diagnosis?
The diagnosis is nipple adenoma, a benign proliferation of the lactiferous ducts in the nipple.
What histopathological features help differentiate nipple adenoma from mammary ductal carcinoma?
Nipple adenoma lacks cytological atypia and has a retained myoepithelial cell layer, which can be confirmed by immunohistochemistry.
What are the clinical features of Adenoid Cystic Carcinoma (ACC)?
Primary cutaneous ACC typically presents as a slow-growing nodule, averaging 2-3 cm in size, often located on the head, neck, or scalp, and can also appear on the trunk or extremities.
What is the histopathological appearance of Adenoid Cystic Carcinoma?
Classic histologic appearance includes dermal islands of basaloid cells arranged in a cribriform pattern with ‘punched-out’ pseudocysts filled with mucin. Mucin is detected by Alcian blue stain (pH 2.5). Tubular and solid growth patterns can also be observed.
What is the prognosis for primary cutaneous Adenoid Cystic Carcinoma compared to its salivary gland counterpart?
The prognosis for primary cutaneous ACC is generally better than that of salivary gland ACC, which has a poor long-term survival rate. Recurrence is frequent in primary cutaneous ACC, possibly due to high rates of perineural invasion, but metastases are rare.
What are the clinical features of Apocrine Adenocarcinoma?
Apocrine Adenocarcinoma typically occurs in elderly adults, presenting as a dermal nodule ranging from 0.5 to 7.5 cm in size. It is most frequently found in areas with a high distribution of apocrine glands, such as the axilla, anogenital region, and scalp.
What are the histological characteristics of Apocrine Adenocarcinoma?
The tumor displays apocrine differentiation with decapitation secretion and malignant features, including atypical architecture and cytological atypia. It has irregular or infiltrative borders and may extend into subcutaneous fat, with various growth patterns including tubular, tubulopapillary, and solid.
What management strategies are recommended for Apocrine Adenocarcinoma?
Wide excision is the treatment of choice due to the risk of metastatic disease and its associated poorer prognosis. Sentinel lymph node biopsy is also advocated at the time of excision to assess for metastasis.
A patient presents with a slow-growing nodule on the scalp. Histopathology reveals dermal islands of basaloid cells arranged in a cribriform pattern with pseudocysts filled with mucin. What is the likely diagnosis?
The likely diagnosis is Adenoid Cystic Carcinoma (ACC), a malignant adnexal neoplasm with characteristic histopathology of basaloid cells in a cribriform pattern and pseudocysts filled with mucin.
What genetic translocation is associated with salivary gland Adenoid Cystic Carcinoma (ACC), and how does it relate to primary cutaneous ACC?
Salivary gland ACC is associated with the t(6;9)(q22-23;p23-24) translocation, resulting in a MYB-NFIB gene fusion. This fusion or MYB overexpression is also observed in primary cutaneous ACC, suggesting a shared oncogenic pathway.
A patient has a dermal nodule in the axilla with tubular and solid growth patterns. What tumor should be considered, and what is the primary site of origin?
The tumor to consider is Apocrine Adenocarcinoma, a rare malignant appendage neoplasm with apocrine differentiation. The axilla is the most frequent site of origin.
What immunohistochemical markers can help distinguish primary cutaneous Adenoid Cystic Carcinoma (ACC) from Basal Cell Carcinoma (BCC)?
Primary cutaneous ACC is positive for CK15, CK7, CD117, EMA, and CEA, while BCC is negative for these markers.
What are the histological characteristics of primary cutaneous cribriform carcinoma?
Primary cutaneous cribriform carcinoma is histologically characterized by:
- Relatively well-circumscribed, dermal neoplasm
- Composed of connected, solid aggregates of basaloid cells
- Features characteristic ‘punched out’ cribriform spaces
- Exhibits indolent behavior with no reported recurrences or metastases.
What immunohistochemical markers are expressed in primary cutaneous cribriform carcinoma?
Primary cutaneous cribriform carcinoma expresses several immunohistochemical markers, including:
- Cytokeratins (CK7, CK5/CK6)
- GCDFP-15
- CEA
- EMA
- Estrogen receptor (ER)
- Progesterone receptor (PR)
- Androgen receptor
What is the clinical significance of local recurrence in primary cutaneous mucinous carcinoma?
Local recurrence of primary cutaneous mucinous carcinoma is significant as it occurs at a reported rate between 30% and 43%. However, clinically aggressive behavior is extremely rare, indicating that while recurrence is common, it may not necessarily lead to aggressive disease progression.
What are the typical clinical features of mucinous carcinoma?
Mucinous carcinoma typically presents with:
- Malignant appendage neoplasm
- Solitary, flesh-colored nodule
- Commonly found on the head, scalp, eyelids, and face
- Classically composed of nests of epithelial cells floating within pools of mucin, with potential heterogeneity between tumors.
What is the recommended management for primary cutaneous mucinous carcinoma?
The recommended management for primary cutaneous mucinous carcinoma is:
- Surgical excision
- Clinical history, imaging, and site of involvement must be evaluated to rule out metastatic disease.
A patient presents with a dermal tumor expressing CK7, CK5/CK6, and GCDFP-15. What is the likely diagnosis, and what is its clinical behavior?
The likely diagnosis is Primary Cutaneous Cribriform Carcinoma, a rare appendage tumor with indolent behavior and no reported recurrences or metastases.
What histological feature helps distinguish Primary Cutaneous Cribriform Carcinoma from metastatic mammary apocrine carcinoma?
Primary Cutaneous Cribriform Carcinoma is adipophilin-negative, ER-positive, PR-positive/negative, HER2-negative, CK5/CK6-positive, and mammaglobin-positive, distinguishing it from mammary apocrine carcinoma.
What are the different phases that the hair follicle cycles through?
The hair follicle cycles through three different phases: anagen, telogen, and catagen.
What is the clinical presentation of Trichofolliculoma?
Trichofolliculoma typically presents as a rare, benign entity that appears as a single, flesh-colored papule in the head and neck region of adults, often with a central dell and protruding vellus hairs.
What are the characteristic histopathologic findings of Trichofolliculoma?
Characteristic histopathologic findings include a central dilated or cystic infundibulum and secondary hair follicles radiating into the dermis, surrounded by connective tissue. The hair follicles can display different stages of differentiation from immature to mature hair follicles.
What is the treatment of choice for Trichofolliculoma?
The treatment of choice for Trichofolliculoma is surgical excision, with an emphasis on cosmesis.
What differentiates folliculosebaceous cystic hamartoma from Trichofolliculoma?
Folliculosebaceous cystic hamartoma typically has mesenchymal differentiation (e.g., into adipose tissue) and prominent sebaceous differentiation, unlike Trichofolliculoma which shows differentiation toward all portions of the hair follicle.
What is Basal Cell Carcinoma in terms of follicular differentiation?
Basal Cell Carcinoma is a malignant neoplasm of follicular germinative differentiation, discussed in detail in Chapter 111.
A patient has a solitary, flesh-colored papule on the nose with a central dell and protruding vellus hairs. What is the diagnosis?
The diagnosis is Trichofolliculoma, a rare benign follicular hamartoma showing differentiation toward all portions of the hair follicle.
What histological features are characteristic of Trichofolliculoma?
Trichofolliculoma shows a central dilated or cystic infundibulum with secondary hair follicles radiating into the dermis, surrounded by connective tissue.
What are the characteristics of trichoblastoma?
- Benign neoplasm showing differentiation toward both follicular germinative and stromal cells.
- Typically presents as a flesh-colored to red dermal nodule on the head and neck, with possible involvement of the trunk and extremities.
- Composed of nests of basaloid cells in a cellular stroma with a variety of patterns, including nodular and trabecular.
- Features clefting within the stroma and may show abortive follicular structures called papillary mesenchymal bodies.
- Malignant transformation to trichoblastic carcinoma or sarcoma is extremely rare, but complete surgical excision is recommended due to the difficulty in distinguishing it from basal cell carcinoma.
What is the differential diagnosis for trichoblastoma?
- The main differential diagnosis (DDx) for trichoblastoma is Basal Cell Carcinoma (BCC).
- Trichoblastoma typically shows:
- Little cytologic atypia
- A low mitotic rate
- Absent necrosis (though single-cell apoptosis can occur)
- Clefting within the stroma
- In contrast, BCC often displays:
- Cytologic atypia
- Frequent mitoses
- Necrosis
- Stromal mucinosis
- Clefting between the epithelial nests and the tumor stroma.
What immunohistochemical markers are useful in distinguishing trichoblastoma from basal cell carcinoma?
Marker | Trichoblastoma | Basal Cell Carcinoma |
|——–|—————-|———————|
| CK20 | Absent | Present |
| CD10 | Stains stromal cells | Highlights epithelial cells |
| CK17 | Weak peripheral staining | Strong diffuse staining |
| Drebin | Weak staining | Strong expression |
- CD10 is useful in highlighting the stromal cells in trichoblastoma, while it highlights epithelial cells in basal cell carcinoma.
- CK20+ Merkel cells are typically absent in basal cell carcinoma but commonly found in trichoblastoma.
What is the recommended management for trichoblastoma?
-
Complete surgical excision is recommended for trichoblastoma due to:
- The low risk of malignant transformation.
- The difficulty in distinguishing it from basal cell carcinoma on small biopsies.
- Mohs micrographic surgery may be considered for solitary lesions, especially if the histologic evaluation suggests malignancy.
A patient presents with a dermal nodule on the head and neck. Histology shows basaloid nests in a cellular stroma with clefting within the stroma. What is the diagnosis?
The diagnosis is Trichoblastoma, a benign neoplasm showing differentiation toward both follicular germinative and follicular stromal cells.
What immunohistochemical marker can help distinguish Trichoblastoma from Basal Cell Carcinoma (BCC)?
CK20+ Merkel cells are commonly found in Trichoblastoma but are absent in BCC.
What are the common clinical presentations of desmoplastic trichoepithelioma?
Desmoplastic trichoepithelioma typically presents as a single, white to yellow, firm papule or plaque with a central depression, frequently found on the face, particularly on the cheek and nose. It can also appear as multiple small papules on the face, often involving the nasolabial folds and sometimes occurring in an X-like pattern.
What genetic mutations are associated with multiple trichoepitheliomas?
Mutations in the CYLD gene on chromosome 16 are associated with multiple trichoepitheliomas, similar to Brooke-Spiegler syndrome. Additionally, deletions of the PTCH1 gene locus at 9q22 have been found in some trichoepitheliomas.
What are the differential diagnoses for trichoepithelioma and desmoplastic trichoepithelioma?
The differential diagnoses (DDx) for trichoepithelioma include Basal Cell Carcinoma (BCC), while for desmoplastic trichoepithelioma, the DDx includes BCC, microcystic adnexal carcinoma, and sometimes syringoma. Both conditions tend to have symmetric growth and lack invasion into the surrounding dermis.
What immunohistochemical markers can help distinguish desmoplastic trichoepithelioma from basal cell carcinoma?
PHLDA1 expression has been suggested as an immunohistochemical tool to distinguish desmoplastic trichoepithelioma (PHLDA1+) from basal cell carcinoma (PHLDA1−). Additionally, CK20+ Merkel cells are more prevalent in desmoplastic trichoepithelioma than in BCC or microcystic adnexal carcinoma.
What treatment options are available for multiple facial trichoepitheliomas?
Treatment options for multiple facial trichoepitheliomas focus on cosmesis and can be challenging. Ablative methods such as electrosurgery, cryosurgery, and laser treatment have been employed, along with topical treatments like imiquimod.
A middle-aged patient presents with multiple small papules on the face, particularly in the nasolabial folds. What is the likely diagnosis?
The likely diagnosis is Multiple Trichoepitheliomas, which are associated with autosomal dominant inheritance and syndromes like Brooke-Spiegler syndrome.
What genetic mutation is associated with Multiple Trichoepitheliomas?
Multiple Trichoepitheliomas are associated with mutations in the CYLD gene on chromosome 16.
A patient has a dermal tumor with basaloid cells in a sclerotic stroma and a central depression. What is the diagnosis?
The diagnosis is Desmoplastic Trichoepithelioma, a variant of Trichoepithelioma.
What immunohistochemical marker can help distinguish Desmoplastic Trichoepithelioma from Basal Cell Carcinoma (BCC)?
PHLDA1 is positive in Desmoplastic Trichoepithelioma but negative in BCC.
What are the clinical features of trichodiscoma/fibrofolliculoma?
- Adult patients over a wide age range
- Firm, white to flesh-colored papule, measuring between 1-3 mm
- Typically observed on the face, but can also be present on the trunk
- Multiple lesions are associated with Birt-Hogg-Dubé syndrome
What is the etiology and pathogenesis of trichodiscoma/fibrofolliculoma?
- Multiple trichodiscomas/fibrofolliculomas are manifestations of Birt-Hogg-Dubé syndrome, an autosomal dominant syndrome caused by mutations in the folliculin (FLCN) gene on chromosome 17.
- Patients with Birt-Hogg-Dubé syndrome have an increased risk of renal tumors, lung cysts, and recurrent pneumothoraces.
How can trichodiscoma/fibrofolliculoma be differentiated from other tumors?
- When stromal differentiation predominates, neural tumors enter into the histologic differential diagnosis.
What are manifestations of Birt-Hogg-Dubé syndrome?
Multiple trichodiscomas/fibrofolliculomas are manifestations of Birt-Hogg-Dubé syndrome, an autosomal dominant syndrome caused by mutations in the folliculin (FLCN) gene on chromosome 17.
What are the risks associated with Birt-Hogg-Dubé syndrome?
Patients with Birt-Hogg-Dubé syndrome have an increased risk of renal tumors, lung cysts, and recurrent pneumothoraces.
How can trichodiscoma/fibrofolliculoma be differentiated from other tumors?
When stromal differentiation predominates, neural tumors enter into the histologic differential diagnosis but can be easily distinguished by S100 immunohistochemistry, which is negative in trichodiscoma/fibrofolliculoma. Histologically, trichodiscomas are composed predominantly of fibrous stromal elements with islands of mature sebaceous lobules at the periphery.
What is the clinical course and prognosis of trichodiscoma/fibrofolliculoma?
Trichodiscoma/fibrofolliculoma is benign, but given its association with Birt-Hogg-Dubé syndrome, genetic screening should be considered for patients with the neoplasm.
What management strategies are recommended for trichodiscoma/fibrofolliculoma?
Laser ablation of multiple trichodiscomas/fibrofolliculomas results in short-term improvement with eventual regrowth.
What syndrome should be considered for a patient with multiple flesh-colored papules on the face and trunk?
Birt-Hogg-Dubé syndrome should be considered, associated with mutations in the folliculin (FLCN) gene on chromosome 17.
What histological features are characteristic of Trichodiscoma/Fibrofolliculoma?
Trichodiscoma/Fibrofolliculoma shows fibrous stromal elements with islands of mature sebaceous lobules or radially oriented epithelial cords.
What is the definition and clinical feature of pilomatricoma?
Pilomatricoma is a benign neoplasm with follicular differentiation, initially described as ‘calcifying epithelioma of Malherbe’ in 1880. It is most common in children and young adults, presenting as a firm, asymptomatic, slow-growing nodule between 1-1.5 cm in size, primarily located on the head and neck, followed by the upper extremities.
What are the histopathological characteristics of pilomatricoma?
Pilomatricoma exhibits a characteristic histologic appearance with a well-circumscribed dermal nodule containing peripheral, nucleated basaloid cells and central, enucleated eosinophilic ‘ghost’ cells. The basaloid cells have hyperchromatic, round nuclei and scant cytoplasm, resembling the matrical cells of the normal hair follicle.
What is the management strategy for pilomatricoma?
The treatment of choice for pilomatricoma is wide local surgical excision. Local recurrences following surgery are uncommon.
What are the clinical features and prognosis of pilomatrical carcinoma?
Pilomatrical carcinoma is a rare malignant appendage neoplasm, most often found in middle-aged to elderly white males. It presents as a rapidly growing dermal nodule, frequently in the head and neck region. Local recurrence is common and poses a risk for locoregional metastasis, with distant metastatic disease and death reported in association with this carcinoma.
What are the histological features that favor malignancy in pilomatrical carcinoma?
Histological features favoring malignancy in pilomatrical carcinoma include infiltrative growth, necrosis, and conspicuous follicular matrical differentiation. The presence of pleomorphic basaloid cells with frequent mitoses and desmoplastic stroma also supports a diagnosis of malignancy.
What is the diagnosis for a child with a firm, slow-growing nodule on the head showing basaloid cells with central eosinophilic ghost cells?
The diagnosis is Pilomatricoma, a benign neoplasm with follicular differentiation.
What genetic mutation is implicated in the pathogenesis of Pilomatricoma?
Pilomatricoma is associated with mutations in the CTNNB1 gene encoding β-catenin, implicating WNT signaling.
What is the diagnosis for a middle-aged patient with a rapidly growing dermal nodule on the head showing pleomorphic basaloid cells with central necrosis?
The diagnosis is Pilomatrical Carcinoma, a rare malignant appendage neoplasm.
What histological features help distinguish Pilomatrical Carcinoma from Pilomatricoma?
Pilomatrical Carcinoma shows cytologic pleomorphism, infiltrative growth, and necrosis, whereas Pilomatricoma does not.
What are the clinical features of trichilemmoma?
- Benign neoplasm
- Adults over a wide age range
- Single or multiple lesions, flesh-colored papules with a verrucous surface
- Predilection for the head and neck, especially the nose
- Associated with Cowden syndrome (multiple hamartoma syndrome) and oral mucosa involvement.
What is the histopathological characteristic of trichilemmoma?
- Well-circumscribed tumor with endophytic lobules extending from the epidermis into the dermis
- Lobules composed of pale eosinophilic keratinocytes with peripheral palisading
- Surrounded by a thick, PAS-positive hyaline membrane
- Desmoplastic variant shows central strands of pale eosinophilic keratinocytes in a fibrotic stroma.
What is the differential diagnosis for trichilemmoma?
Trichilemmoma can resemble:
- Wart
- Basal Cell Carcinoma (BCC)
- Seborrheic keratosis
- Clear-cell poroma
- Clear-cell acanthoma
- Infiltrative carcinoma, including Squamous Cell Carcinoma (SCC) and BCC, is also in the differential diagnosis of desmoplastic trichilemmoma.
What is the management strategy for trichilemmoma?
Trichilemmomas are managed by:
1. Surgical excision
2. Laser ablation
- Trichilemmal carcinoma is treated by surgical excision using either conventional or Mohs micrographic techniques.
What syndrome should be considered for a patient with multiple flesh-colored papules on the nose and oral mucosa?
Cowden syndrome should be considered, associated with mutations in the PTEN tumor-suppressor gene.
What histological features are characteristic of Trichilemmoma?
Trichilemmoma shows endophytic lobules of pale keratinocytes with peripheral palisading, surrounded by a PAS-positive hyaline membrane.
What are the clinical features of Tumor of Follicular Infundibulum?
- Adult patients with an average age in the sixth decade
- No sex predilection
- Solitary keratotic papule on the head and neck
- Multiple tumors can present as hypopigmented macules, also located on the head and neck.
What is the histopathological characteristic of Tumor of Follicular Infundibulum?
- Composed of strands of eosinophilic, isthmic keratinocytes that extend from the epidermis into the superficial dermis in a reticular pattern.
- Special stains reveal a ‘brush-like’ network of elastic fibers that surround the base of the tumor.
- Tumor cells are negative for BerEP4 and show scattered CK20+ Merkel cells, in contrast to BCC.
What is the management strategy for Tumor of Follicular Infundibulum?
- Topical steroids
- Retinoids
- Cryotherapy
- Curettage
- Surgery
All treatments show limited results, especially in patients with multiple tumors.
What are the clinical features of Pilar Sheath Acanthoma?
- Adult patients over a wide age range without apparent sex predilection
- Single, flesh-colored nodule with a central keratotic plug, often on the head.
What is the histopathological differentiation of Pilar Sheath Acanthoma?
- Differentiation toward both infundibular and isthmic portions of the normal hair follicle.
- Well-circumscribed cystic epithelial proliferation with superficial/central infundibulo-cystic differentiation and peripheral isthmic differentiation.
What is the management for Pilar Sheath Acanthoma?
Surgical excision for cosmetic purposes.
What is the diagnosis for a patient with a keratotic papule on the head showing eosinophilic keratinocytes in a reticular pattern?
The diagnosis is Tumor of Follicular Infundibulum, a rare benign appendage neoplasm.
What histological feature distinguishes Tumor of Follicular Infundibulum from Basal Cell Carcinoma (BCC)?
Tumor of Follicular Infundibulum is negative for BerEP4 and shows scattered CK20+ Merkel cells, unlike BCC.
What are the characteristics of proliferating pilar tumors?
- Typically found in adult patients in their sixth decade or older.
- Marked female predilection.
- Present as a dermal nodule on the scalp, averaging 3 cm in size, but can be up to 25 cm.
- Can occur as single or multiple lesions.
- Follicular neoplasm with differentiation toward the outer root sheath.
- Characteristic trichilemmal keratinization with an abrupt transition from squamous epithelium to glassy, compact keratin without a granular cell layer.
What is the clinical significance of distinguishing proliferating pilar tumors from squamous cell carcinoma (SCC)?
- Proliferating pilar tumors can be difficult to distinguish from SCC, especially in areas of solid growth or limited biopsies.
- Identification of squamous eddies, trichilemmal keratinization, or remnants of a pilar cyst can aid in differentiation.
- Proliferating pilar tumor cells show positive staining for AE13, AE14, and CD34, while SCC tumor cells show negative staining for these markers.
What are the grading categories for proliferating pilar tumors based on histologic features?
- Benign: Good circumscription, minimal cytologic atypia, no known recurrences.
- Low-grade malignant: Invasion into surrounding tissues, moderate cytologic atypia, no local disease recurrence.
- High-grade malignant: Invasive, displays anaplastic cytologic atypia, has recurrences and cases of metastatic disease.
What is the recommended treatment for malignant proliferating pilar tumors?
- Complete surgical excision is recommended.
- Both conventional and Mohs micrographic surgical techniques have been utilized.
- Chemotherapy and radiotherapy have shown limited therapeutic benefit in patients with malignant proliferating pilar tumors.
What is the diagnosis for a patient with a single flesh-colored nodule on the upper lip with a central keratotic plug?
The diagnosis is Pilar Sheath Acanthoma, a rare benign appendage neoplasm.
What histological features are characteristic of Pilar Sheath Acanthoma?
Pilar Sheath Acanthoma shows a central cystic cavity with radially oriented lobules of eosinophilic keratinocytes showing isthmic differentiation.
What is the diagnosis for a patient with a large dermal nodule on the scalp showing trichilemmal keratinization and peripheral palisading?
The diagnosis is Proliferating Pilar Tumor, a follicular neoplasm with differentiation toward the outer root sheath.
What histological features help distinguish Proliferating Pilar Tumor from Squamous Cell Carcinoma (SCC)?
Proliferating Pilar Tumor shows trichilemmal keratinization, squamous eddies, and positive staining for AE13, AE14, and CD34, unlike SCC.
What are the clinical features of trichoadenoma?
- Flesh-colored papule on the face or buttock
- Occurs in adults
- No apparent gender predilection
What is the histopathological characteristic of a dilated pore (of Winer)?
- Dilated infundibulum oriented perpendicularly to the epidermal surface
- Epithelial projections resembling rete ridges radiate from the central pore
- Epithelial atrophy at the ostium filled with lamellar orthokeratosis
What is the management approach for trichoadenoma?
Excision for cosmetic purposes
How does a dilated pore differ histologically from pilar sheath acanthoma?
- A dilated pore shows infundibular differentiation, while pilar sheath acanthoma shows isthmic differentiation with eosinophilic or clear cytoplasm.
- The epithelial projections in dilated pore are less bulbous than those in pilar sheath acanthoma.
What are the characteristics of sebaceous neoplasms?
- Show sebaceous differentiation
- Characterized by mature sebocytes with vacuolated cytoplasm and scalloped nuclei
What is the diagnosis for a patient with a flesh-colored papule on the face showing infundibulocystic structures within a fibrotic stroma?
The diagnosis is Trichoadenoma, a benign follicular neoplasm with differentiation toward the infundibulum.
What histological features help distinguish Trichoadenoma from Trichoepithelioma and Microcystic Adnexal Carcinoma?
Trichoadenoma shows infundibulocystic structures within a fibrotic stroma, which are distinct from the features of Trichoepithelioma and Microcystic Adnexal Carcinoma.
What is the diagnosis for a patient with a single papule on the head filled with keratinaceous material?
The diagnosis is Dilated Pore (of Winer), a benign follicular neoplasm with differentiation toward the infundibulum.
What histological features are characteristic of Dilated Pore (of Winer)?
Dilated Pore shows a dilated infundibulum oriented perpendicularly to the epidermis with epithelial projections resembling rete ridges.
What are the clinical features of sebaceous adenoma?
Sebaceous adenomas are benign neoplasms typically found in adult patients, presenting as single or multiple tan, pink, or yellow papules, usually around 0.5 cm in size, located on the head and neck.
What is the pathogenesis associated with sebaceous adenomas?
Sebaceous adenomas are associated with Muir-Torre syndrome, an autosomal dominant cancer predisposition syndrome caused by mutations in DNA mismatch repair genes. They display a lobular architecture with central mature sebocytes and peripheral basaloid germinative cells, with less than 50% of the tumor volume being basaloid germinative cells.
What is the prognosis for sebaceous adenomas?
Sebaceous adenomas are benign but can be associated with Muir-Torre syndrome. Complete excision is recommended, and screening for Muir-Torre syndrome is advised, as these adenomas can be the presenting feature.
What are the clinical features of sebaceoma/sebaceous epithelioma?
Sebaceomas typically occur in adults in their fifth and sixth decades, presenting as orange-yellow papules ranging from 0.5 to 1 cm in size, primarily located in the head and neck region.
What distinguishes sebaceoma from sebaceous carcinoma in histological diagnosis?
In small and/or superficial biopsies, distinguishing between sebaceoma and sebaceous carcinoma can be challenging. Sebaceomas are well-circumscribed dermal nodules with greater than 50% basaloid germinative cells, while cytologic atypia is rare. Immunohistochemical stains for BerEP4 and EMA can help differentiate between basal cell carcinoma and sebaceoma.
What is the prognosis for sebaceomas?
Sebaceomas are benign neoplasms that typically do not have an aggressive clinical course. Surgical excision is recommended, along with screening for Muir-Torre syndrome.
What are the characteristics of sebaceomas?
Sebaceomas are well-circumscribed dermal nodules with greater than 50% basaloid germinative cells, while cytologic atypia is rare.
What is the diagnosis for a patient with a yellow papule on the head and lobular architecture with central mature sebocytes?
The diagnosis is Sebaceous Adenoma, a benign neoplasm with sebaceous differentiation.
What syndrome is associated with Sebaceous Adenoma?
Sebaceous Adenoma is associated with Muir-Torre syndrome, caused by mutations in DNA mismatch repair genes (MLH1, MSH2, MSH6, PMS2).
What is the diagnosis for a patient with an orange-yellow papule on the head and >50% basaloid germinative cells?
The diagnosis is Sebaceoma, a benign sebaceous neoplasm.
What immunohistochemical markers can help distinguish Sebaceoma from Basal Cell Carcinoma (BCC)?
Sebaceoma is BerEP4-negative and EMA-positive, while BCC is BerEP4-positive and EMA-negative.
What are the clinical features of sebaceous carcinoma?
Sebaceous carcinoma presents as a painless, slow-growing nodule, more common in ocular sites than extraocular sites. Incidence is 54% in men and 46% in women, particularly in the elderly.
What is the histopathological characteristic of sebaceous carcinoma?
Sebaceous carcinoma is characterized by poorly differentiated basaloid cells growing in sheets with an infiltrative growth pattern, cytological atypia, and frequent mitoses.
What are the differential diagnoses for sebaceous carcinoma?
The differential diagnosis includes benign lesions like chalazion and blepharitis, poorly differentiated carcinomas like BCC, SCC, and metastatic carcinoma, as well as melanoma in situ.
What factors influence the prognosis of sebaceous carcinoma?
Prognostic factors include delayed diagnosis, tumor size > 1 cm, histologic factors like poor differentiation, pagetoid spread, multicentricity, and lymphovascular or perineural invasion.
What management strategies are recommended for sebaceous carcinoma?
Management strategies include wide excision, adjuvant radiation if regional lymph node metastases are detected, and sentinel lymph node biopsy.
What is the diagnosis for a patient with a painless, slow-growing nodule on the eyelid and poorly differentiated basaloid cells with pagetoid spread?
The diagnosis is Sebaceous Carcinoma, a rare malignant sebaceous neoplasm.
What immunohistochemical markers can help distinguish Sebaceous Carcinoma from BCC and SCC?
Sebaceous Carcinoma is positive for adipophilin and androgen receptor, while BCC and SCC are negative for these markers.
What are poor prognostic factors for Sebaceous Carcinoma?
Poor prognostic factors include delayed diagnosis, tumor size >1 cm, poor differentiation, pagetoid spread, multicentricity, and lymphovascular or perineural invasion.
What is the significance of categorization in orbital sebaceous carcinoma?
Categorization is important as sebaceous carcinoma occurring in extraocular sites is more frequently associated with Muir-Torre syndrome.
What staining is found to be positive in up to 80% of sebaceous carcinomas?
BerEP4 staining is found to be positive in up to 80% of sebaceous carcinomas.
What is the clinical significance of Nuclear factor XIIIa staining in sebaceous carcinoma?
Nuclear factor XIIIa staining is highly sensitive for sebaceous differentiation compared to clear-cell carcinomas.
What is the recommendation for screening Muir-Torre syndrome in patients with ocular sebaceous carcinomas?
Screening for Muir-Torre syndrome is particularly recommended if patients are younger than 50 years old and/or if the tumor arises in a site other than the head and neck.
What is the most common appendage tumor in children?
The most common appendage tumor in children is pilar cyst.
