dermatopathology
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Clinical features •Head (scalp), neck, limbs but can occur anywhere •Slowly grown sharply circumscribed flesh colored/erythematous or blue nodule or cystic nodule 0.5-3 cm diameter •Generally symptomatic but can be pruritic or tender •Mostly 3rd– 5th decades (3-93 years) •Slight predominance in females Histological features •Solid or cystic sharply defined nodule in dermis sometimes extending into subcutaneous fat •Eccrine (predominantly poroid & cuticular cells) & apocrine variants (association with a follicle, decapitation secretion & GCDFP-15+ve) •May overlap with poroma…
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Clinical features •May present as an intraepidermal lesion (hidroacanthoma simplex, a dermal tumor (dermal duct tumor) or as both with epidermal continuity (poroma); some tumors overlap hidradenoma & poroma (poroid hidradenoma overlap) •Solitary skin colored, erythematous or pigmented, generally asymptomatic nodule with a predilection for the foot but it may occur just about anywhere •M=F…
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Trichilemmoma is a tumor showing differentiation towards the follicular external root sheath. It may be solitary, multiple or constitute a features of autosomal dominant, Cowden (multiple hamartoma) syndrome when very numerous lesions are present. The last is associated with germline mutations in the PTEN tumor suppressor gene in the majority of patients. Solitary lesions do…
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A relatively common benign sweat gland tumor characterised by an admixture of epithelial & mesenchymal elements. Typically thought of an apocrine gland tumor. Some authors recognise an eccrine variant. In my experience, such tumors are exceptionally rare. Many tumors show an admixture of both elements. Mixed tumor of the skin is mostly associated with rearrangment…
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Clinical features •Very rare •Solitary– elderly F>M, 1-2 mm skin-colored papule with a predilection for the face & scalp but may occur elsewhere •Localized– pink or brown plaque with a predilection for scalp, +/- milia & alopecia •Linear nevoid– congenital/acquired, dermatomal, can be very extensive +/- alopecia, BCC, epidermoid cysts & comedones •Segmental– associated with osseous & dental malformations &…
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The entities trichoblastic fibroma, trichogenic trichoblastoma, giant solitary trichoepithelioma, subcutaneous trichoepithelioma, immature trichoepithelioma are all included under the rubric trichoblastoma. Trichoblastoma shared many histological similarites with trichoepithelioma but differs by its much larger size, extension into the deep dermis/subcutaneous fat or deeper and large circumscribed nodules Papillary mesenchymal bodies are often absent or more difficult…
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Considered by some authors to represent a variant of trichoblastoma (adamantoid trichoblastoma, lymphoepithelial tumor (not to be confused with lymphoepithelioma-like carcinoma) Clinical features •Solitary skin colored or erythematous papule, nodule or plaque up to 1.0 cm diameter •Overlying telangiectasia may result in confusion with BCC •Exceptionally multiple •Predilection for the face (cheek, eyebrow, forehead) •Exceptionally, neck, shoulder & leg…
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Trichoepithelioma is a hamartoma comprising a basaloid/germinative component and a prominent perifolliclular sheath proliferation. It may present as a solitary lesion or as multiple, familial lesions in multiple familial trichoepithelioma (which is probably a variant of Brook-Spiegler syndrome) & Brook-Spiegler syndrome. Clinical features •Solitary trichoepithelioma presents as a flesh-colored papule or nodule (<1.0 cm) most…
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Sebaceous hyperplasia Clinical features •This is common and presents as single or commonly multiple, yellow dome-shaped umbilicated papule(s) (1-2 mm diameter) on face of the elderly but may occur on the chest, the caruncle, external genitalia & areola •M>F •Increased incidence with cyclosporine Histological features •Lobules drain into a dilated follicle •Lobules are increased in number but do not…
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•The late Bernie Ackerman classified acquired melanocytic nevi into Miescher nevus which most commonly occurs on the face and Unna nevus which generally presents on or below the neck •Miescher nevus is typically dome-shaped •In Miescher nevus, the nevus is generally dermal, wedge shaped & extends into the reticular dermis •Unna nevus presents as an exophytic, light to dark brown, polypoid,…
McKee Derm 