microcystic adnexal carcinoma


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Related to microcystic adnexal carcinoma: desmoplastic trichoepithelioma

microcystic adnexal carcinoma

A rare (circa 300 cases in the world literature) malignant skin appendage tumour, usually typed as a low-grade sweat gland carcinoma which occurs on the head and neck, and especially on the central face. It is locally aggressive and invades bone, muscle, blood vessels, cartilage, and nerves, but rarely metastasises. It presents as a clinical lesion averaging 3 cm2, but leaves an average post-surgical defect of 18 cm2, due to occult extension.

Epidemiology
Adults (median age 50; range 10 to 90).

DiffDx
Syringoma, desmoplastic trichoepithelioma, adenosuamous carcinoma, trichoadenoma, morphoeic BCC, metastatic breast carcinoma, small cell carcinoma.

Prognosis
It is locally aggressive, but rarely metastasises.

Aetiology
20–50% of patients have a history of therapeutic radiation with a 30-year average latency; UV light has also been implicated.
 
DiffDx
Desmoplastic trichoepithelioma, syringoma, trichoadenoma.
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References in periodicals archive ?
(70) See the section on Microcystic Adnexal Carcinoma above for a discussion regarding distinguishing DTE from MAC based on H&E features.
Microcystic adnexal carcinoma: review of 51 Japanese patients.
Microcystic adnexal carcinoma of the skin: a reappraisal of the differentiation and differential diagnosis of an under-recognized neoplasm.
The immunohistochemical differential diagnosis of microcystic adnexal carcinoma, desmoplastic trichoepithelioma and morpheaform basal cell carcinoma using BerEP4 and stem cell markers.
Microcystic adnexal carcinoma. A, Horn cysts in the superficial portion of the tumor give way to small strands with ductal differentiation in the deeper aspect of the tumor.
(61,64,68,69) Although p75NTR is more likely to show diffuse expression in DTE than in mBCC, (70) a later study (71) demonstrated limited specificity, with diffuse expression in 36% of mBCC and 44% of microcystic adnexal carcinomas. In recent studies, strong and diffuse expression of PHLDA1 (TDAG51), a follicular stem-cell marker, has been shown to be highly specific for TE/TB, (53,55,72) although expression in micronodular BCC has been reported.