Microcystic adnexal carcinoma: treatment with Mohs micrographic surgery.

BACKGROUND: Microcystic adnexal carcinoma (MAC) is reported to have a high rate of recurrence with standard wide local excision.

OBJECTIVE: To report a large series of patients with MAC treated with Mohs micrographic surgery (MMS).

METHODS: This prospective, multi-center case series included all patients in Australia treated with MMS for MAC, who were monitored by the Skin and Cancer Foundation between 1993 and 2002.

RESULTS: There were 44 cases; most of them (90.9%) were located in the head and neck area. In 31.8% of cases it was a recurrent tumor. In 32.5% of cases the tumor was initially misdiagnosed as basal cell carcinoma or squamous cell carcinoma. Perineural invasion was recorded in 17.5% of cases; most of them (85.7%) were previously recurrent tumors. There was only one case of recurrence (5%) out of 20 patients who completed a 5 year follow-up period after MMS.

CONCLUSION: The low 5-year recurrence rate of MAC with MMS emphasizes the importance of margin-controlled excision.