Secretory carcinoma in the axilla: probable origin from axillary skin appendage glands in a young girl.

Invasive carcinoma in the axilla may arise from skin appendage glands or ectopic breast tissue or it may be a metastasis. Carcinomas of the skin adnexal glands and breast can be difficult to distinguish from each other as they often display the same patterns of growth. Tubular, cribriform, papillary, apocrine, mucinous, and adenoid cystic are histologic types of carcinoma seen in the breast and skin appendage glands. To our knowledge, secretory carcinoma, the most common form of mammary carcinoma in children, has not yet been described as a morphologic pattern of skin adnexal carcinoma, although we cannot exclude the possibility that such a case was reported with a different diagnosis. We report a case of a young girl with secretory carcinoma that seems to have arisen from skin appendage glands in the skin of the axilla in the absence of demonstrable ectopic breast tissue.