Microcystic adnexal carcinoma: report of 13 cases and review of the literature.

ABSTRACT

BACKGROUND: Microcystic adnexal carcinoma (MAC) is a rare tumor of the skin. Clinically it often masquerades as a firm, subcutaneous nodule on the head and neck regions. Microscopically it extends far beyond assessed clinical margins spreading locally in the dermal, subcutaneous, and perineural tissue planes. The local recurrence rate by standard excision is about 50%. Recent preliminary reports indicate more favorable cure rates with Mohs micrographic surgery (MMS). OBJECTIVE: To present our data on 13 cases (12 patients) of MAC treated by MMS. In addition, we reviewed the medical literature to summarize the accumulated experience of MMS treatment in the management of MAC. We also present a case of bilateral MAC of the face and describe a renal transplant recipient on immunosuppressive therapy who developed MAC of the nasal bridge. METHODS: We reviewed and updated our series of MAC cases treated by MMS over the last 9 years. A total of 13 cases of MAC are reviewed. We also searched the literature for MAC treated by MMS with a follow-up of more than 2-years. RESULTS: One patient had bilateral MAC of the nose and cheek. Another patient developed a MAC of the nasal bridge 20 years after renal transplantation. In this patient predisposing factors were radiation for teenage acne and immunosuppression therapy. A total of 13 cases of MAC were treated by MMS with no recurrences, with a mean follow-up of 5.0 years (range 1.1-8.0 years). CONCLUSION: We update the medical literature with 13 MAC cases treated by MMS. To our knowledge there have been 148 cases of MAC reported in the world literature. Including our series, there have been 73 cases of MAC treated with MMS. There were only four treatment failures. Regional and/or distant metastasis from MAC is rare, with only one reported death. Following MMS, the 2-year success rate was 89.7% (35 of 39). The accumulated data continue to confirm that when MAC is discovered early and is readily accessible to excision by MMS and other subspecialty support, a favorable outcome can be expected.