Background: Mohs micrographic surgery (MMS) offers high cure rates and maximum tissue preservation in the treatment of more common cutaneous malignancies, but its effectiveness in rare aggressive tumors is poorly defined.
Objective: Evaluate the effectiveness of MMS in the treatment of six rare aggressive cutaneous malignancies as seen by Mohs surgeons working at a referral center.
Methods: Retrospective chart review of 26,000 cases treated with MMS at the Geisinger Medical Center Department of Dermatology during a 16-year period with the following diagnoses: poorly differentiated squamous cell carcinoma (PDSCC), dermatofibrosarcoma protuberans (DFSP), microcystic adnexal carcinoma (MAC), extramammary Paget's disease (EMPD), Merkel cell carcinoma (MCC), and sebaceous carcinoma (SEB CA). Patient demographic data, tumor measurements, treatment characteristics, and marginal recurrence rates were compiled and evaluated.
Results: The mean numbers of cases identified per year for each tumor type were as follows: PDSCC, 6.19; DFSP, 2.44; MAC, 1.63; and EMPD, 0.63. For PDSCC, 85 cases were available for follow-up with a local recurrence rate of 6% at a mean follow-up time of 45 months. For DFSP, there were 35 cases with no local recurrence at a mean follow-up of 39 months. For MAC, there were 25 cases with a local recurrence rate of 12% at a mean follow-up of 39 months. For EMPD, there were 10 cases with no local recurrences at a mean follow-up of 34 months.
Conclusions: Collectively, our data on PDSCC, DFSP, MAC, and EMPD, combined with other studies in the literature, show that MMS is the most effective therapy for these rare aggressive cutaneous malignancies.