Mohs micrographic surgery for the treatment of hidradenocarcinoma: the Mayo Clinic experience from 1993 to 2013.

Background: Hidradenocarcinoma (HAC) is a rare malignant adnexal neoplasm with reported metastatic potential and undefined optimal treatment.

Objective: To review clinical characteristics and outcomes of patients with HAC treated with Mohs micrographic surgery (MMS).

Methods: The authors performed a retrospective chart review of patients with HAC treated by MMS at Mayo Clinic from 1993 to 2013, recording patient demographics, tumor characteristics, MMS stages to clearance, follow-up, recurrence, metastasis, and mortality.

Results: Ten patients underwent MMS for HAC more than 20 years. The average age was 62.8 years, with 6 females and 4 males. Occipital scalp was the most common location (40%), followed by extremities (30%) and face (20%). In 5 of 7 cases (71%), "cyst" was the working clinical diagnosis. The average preoperative lesion area was 3.18 cm, with an average of 1.5 MMS stages required for clearance. Mean postoperative follow-up was 7 years (range, 5-205 months). No tumors treated with MMS recurred, metastasized, or led to disease-related mortality.

Conclusions: Mohs micrographic surgery seems to be a useful treatment modality for HAC. This is the largest reported series of HAC treated with MMS with long-term follow-up.