Microcystic adnexal c~arcinoma(MAC) is an unusual carcinoma of eccrine glands, composed of pilar and: weat. duct structures. We report here a 64-year-old man with MAC on his left cutaneous upper lip. Microscopically, the tumor consisted of nests and gland-like str~i~ictures within desmoplastic stroma, and it stained positively for carcinoembryonic antigen. The clinical appearance and histopathologic findings of t,he tumor may be mistaken for other benign and malignant entities. The patient was treated with excision and skin flap, and no recurrence over a 31-month follow up period. (Kor J Dermatol 1996;34(5): 823-826)