Merkel cell carcinoma. Comparison of Mohs micrographic surgery and wide excision in eighty-six patients.

BACKGROUND

Merkel cell carcinoma is an uncommon malignant tumor of the skin that, after standard surgical excision, tends to recur locally and develop regional nodal spread.

OBJECTIVE

This study evaluated the use of Mohs micrographic surgery for this aggressive neoplasm.

METHODS

A retrospective study of 86 patients with Merkel cell carcinoma established rates of local persistence and the development of regional metastasis after standard surgical excision. Detailed follow-up was available on a subgroup of 13 patients treated with Mohs surgery.

RESULTS

Standard surgical excision for local disease was associated with high rates of local persistence (13 of 41 [31.7%]) and regional metastasis (20 of 41 [48.8%]). Mean follow-up was 60 months. Mean follow-up for the group treated with Mohs was 36 months. Only one of 12 (8.3%) Mohs-treated patients with histologically confirmed clearance has had local persistence of disease. This patient underwent a second Mohs excision and has remained disease free for 84 months. Regional metastasis developed in four of 12 cases (33.3%). Regional metastasis developed in none of the four patients treated with radiotherapy after Mohs surgery and in four of eight patients treated with Mohs surgery without postoperative radiotherapy.

CONCLUSION

Mohs surgery compares favorably with standard surgical excision. Radiotherapy after Mohs surgery may further reduce persistent metastases in transit and nodal disease.