Microcystic adnexal carcinoma. Report of a case with 30-year follow-up.

Microcystic adnexal carcinoma is a recently described neoplasm characterized by a locally aggressive growth pattern. The tumor usually affects the upper lip of middle-aged women, but occurs in other facial areas and in men. Histologically, a distinctive combination of keratin-filled cysts, islands and strands of basaloid and squamous cells, and ducts and glandlike structures is seen. A dense, hyalinized stroma is also a feature as well as frequent perineural invasion by tumor cells. While microcystic adnexal carcinoma is deeply infiltrating in its growth, metastasis has not been reported. However, recurrences with extensive local tumor spread are often observed. We describe a middle-aged man who initially had a lesion of microcystic adnexal carcinoma excised 30 years prior to definitive treatment for a recurrence at the original site. To our knowledge, this is the longest follow-up of a patient with microcystic adnexal carcinoma and confirms its locally infiltrating, indolent biologic behavior.