Mohs micrographic surgery for squamoid eccrine ductal carcinoma.

BACKGROUND: Squamoid eccrine ductal carcinoma is a rare cutaneous malignancy. There are no accepted standards for surgical margins in eccrine carcinomas. OBJECTIVE: We report a case of squamoid eccrine ductal carcinoma resembling squamous cell carcinoma and discuss Mohs micrographic surgery as a surgical modality for eccrine carcinomas. METHOD: The patient was a 30-year-old Korean woman with a 4-year history of a nodule on her neck. Following primary diagnosis of squamous cell carcinoma by punch biopsy, the tumor was completely removed by Mohs micrographic surgery with a 2 mm cancer-free margin. RESULT: A one-stage Mohs micrographic surgical procedure was performed, and the size of the tumor mass was 2.3 x 2.5 cm in width and 1.5 cm in depth. On histopathologic examination, the tumor was characterized by both eccrine and squamous differentiation. The squamous cells expressed epithelial membrane antigen and cytokeratin 5 and 6, and the cells forming ductal structures expressed anti-carcinoembryonic antigen. Although eccrine carcinomas show a generally aggressive clinical course, the patient was disease free at 14 months after surgery. DISCUSSION: Squamoid eccrine ductal carcinoma should be considered in the differential diagnosis of squamous cell carcinoma and other cutaneous adnexal neoplasms showing squamoid and ductal features of differentiation. In addition, Mohs micrographic surgery can be an option sufficient for complete surgical removal of eccrine carcinomas such as squamoid eccrine ductal carcinoma.