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Although desmoplasia may exceptionally be encountered in banal/common and congenital nevi, the overwhelming majority of cases represent sclerosis in Spitz nevi. Desmoplastic blue neves is discussed in a separate blog. Desmoplastic nevus arising on chronic sun-damaged skin has also been described. Clinical features Desmoplastic Spitz nevus presents as a usually small, erythematous papule or nodule…
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Clinical features •In the older literature also known as juvenile melanoma, spindle & epithelioid cell nevus •First described by Sophie Spitz in 1948 •Approximately 1% of nevi in children •Most often presents in children & adolescents but may be seen the middle aged •Although cases have been documented in the elderly, I would advise extreme…
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This is commonly regarded as a variant of Spitz nevus but as it has such disctinct histological features it is covered in a separate blog. Clinical features •Heavily pigmented papule or nodule, starburst pattern seen with dermoscopy is characteristic •Young people •F>M •Lower limbs> upper limbs> trunk Histological features •Variant of Spitz nevus, readily identifiable…
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Nevi presenting in the genitalia, inguinal region, umbilicus, axilla and breast may show considerable atypia. They should be readily recognised, often at scanning magnification but may be misdiagnosed as melanoma if the age of the patient and site of the lesion are not taken into account. So-called atypical acral nevus, ear & scalp nevi are…
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In the older literature this lesion has previously been called epithelioid blue nevus, animal type melanoma, pigment synthesizing melanoma & equine melanoma. Indeed, my cases of so-called animal type melanoma were re-classified as pigmented epithelioid melanocytoma during the preparation of the seminal paper on the topic by Zembowicz & Carney. Clinical features •Most common in…
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Clinical features •Proliferative nodules arise in giant (& occasionally small) congenital nevi •Develop in 2.9-19% of giant congenital nevi •Lesions can be single or multiple & are generally present at birth •Coloration varies from brown to black although deep seated lesions may not be apparent to the naked eye •The natural history is of spontaneous regression •Their importance is that they may be misdiagnosed by the unwary as neonatal melanoma •Congenital & neonatal melanoma is vanishingly…
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A rare variant of nevoid melanoma wherein the tumor cells have scant cytoplasm, and basophilic, hyperchromic nuclei mimicking type B nevus cells. Typically, the tumor cells are positive for S100, Mart-1 & HMB45. It is of no prognostic importance. It is one of the more often encountered melanoma variants in giant congenital nevi & can…
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•Extremely rare often amelanotic, high-grade variant (based on the majority of documented cases representing metastases. The biological potential of primary tumors with rhabdoid features is uncertain owing to the paucity of reported cases) •Metastases & recurrent disease>>primary tumors •Characterized by pleomorphic tumor cells with large eosinophilic, hyaline globular inclusions and eccentric vesicular nuclei containing prominent nucleoli, mitoses often conspicuous •Inclusions predominantly composed of vimentin intermediate filaments •Immunophenotype is variable with possible loss of expression…
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Clinical fetaures •4% of melanoma cases in the USA •Predominantly affects sun damaged skin of the elderly •Malar region, nose, temple, forehead •Less of back of hand •Variably pigmented slowly growing macule with irregular borders & variable pigmentation •Papule or nodule formation indicates invasive tumor •Hypopigmentation is strongly suggestive of regression Histological features & immunohistochemstry •Epidermal atrophy & solar elastosis •Atypical melanocytes located predominantly along the basal layer of the epidermis, singly,…
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Definition A destinctive melanocytic tumor which may arise sporadically or less often represent a germline mutation in the tumor-suppressor gene BRCA1-associated protein-1 (BAP1). The latter is associated with an increased risk of devloping mesothelioma, uveal melanoma, cutaneous melanoma, Merkel cell carcinoma, basal cell carcinoma, meningioma & renal cell carcinoma Alternative nomenclature •BAP1-inactivated melanocytic tumors (BINT)…
McKee Derm 