An atypical presentation of extensive centrofacial microcystic adnexal carcinoma responding to radiation: A case report and review of the literature.

Microcystic adnexal carcinoma is a rare cutaneous neoplasm believed to arise from pluripotent keratinocytes capable of adnexal differentiation. Due to its insidious growth and appearance, diagnosis is often delayed. A deep incisional or excisional biopsy for histopathology is the gold standard for diagnosis. Different treatment modalities have been described in the literature, including the Mohs micrographic surgery, standard excision, radiation, chemotherapy, and observation. Currently, Mohs remains the treatment of choice. We present a unique case of a 12-month history of an extensive progressive centrofacial cutaneous induration diagnosed as microcystic adnexal carcinoma in an 83-year-old female. Due to the extensive nature of the tumor, she received radiation therapy and continues to receive ongoing assessment with no evidence of clinical recurrence at 2-year post-treatment including negative scouting biopsies. To date, there is no consensus on the optimal treatment for microcystic adnexal carcinoma.