Syringoid Eccrine Carcinoma of the Thigh

Syringoid eccrine carcinoma (SEC) is a rare cutaneous malignant tumor thought to be derived from eccrine sweat apparatus. It is usually present in the head, neck and trunk region, and often occurs in the fourth to seventh decades of life. A 94-year-old male patient visited our department with an 80-year history of a lesion showing a 2×2 cm sized well-demarcated round shaped erythematous to pinkish colored nodule with ulcer on his left thigh. Histological findings revealed a tumor consisted mainly of numerous small cords and nests forming luminal or tubular structures and tumor cells showing variable atypia. Some ductal structures showed tadpole appearance. On immunohistochemical staining, epithelial membrane antigen, S-100, cytokeratin 7 and carcinoembryonic antigen were reactive and Ki-67 showed less than 10% positivity. Based on these findings, the final diagnosis was made as SEC. The patient was treated with local wide excision and didn't show any recurrence during the follow-up period of 12 months. Herein, we report a very rare case of SEC which occurred on the left thigh and discuss 10 cases of SEC presented on the extremities, including our case.