Microcystic Adnexal Carcinoma. A Rare Entity.

Background: Microcystic adnexal carcinoma is a rare malignant tumour derived from sweat glands, locally aggressive, but with low rate of lymphatic or metastatic spread. Tends to affect the deep dermis, without affection of epidermis. Surgery remains as the first line treatment. Case Report: We present a case of a 46-year-old woman with a slow growing lesion of the upper lip, with biopsy diagnosis of microcystic adnexal carcinoma. She underwent a resection and reconstruction with local advancement flaps. The final anatomopathological study showed an adnexal epithelial neoplasm with imprecise borders, poorly delimited, non-encapsulated, growing in plaque-like formation from the superficial dermis into the adipose tissue, perineural invasion, without epidermal infiltration. Discussion: It is an extremely rare malignant tumour, appearing as a solitary papule or plaque affecting the central face, that often affect middle-aged caucasic, female patients. Usual local aggressive nature, characterized by small nests and strands of cells in deep dermis and perineural-invasion images, absent in superficial tissue. An incisional biopsy is need to make a correct diagnosis. Due to its rarity there is no consensus on the best management and follow-up. The microcystic adnexal carcinoma should be taken into consideration in the differential diagnosis.