Primary mucinous carcinoma in a 54-year-old man.

Primary mucinous carcinoma is a rare malignant tumor that most frequently occurs in the periorbital area. This tumor originates from the deepest portion of the eccrine sweat duct. This normally asymptomatic and slow-growing tumor has demonstrated a local recurrence rate of 30% after excision with narrow surgical margins and can have local metastases. It is difficult to differentiate this tumor histologically from metastatic lesions. Immunohistochemical staining and cytokeratin profiles have been studied to aid in the differentiation between primary lesions and metastatic mucinous carcinomas. We present a case of a 54-year-old man with recurrent primary eccrine mucinous carcinoma and review the clinical, histologic, and immunohistochemical features of this tumor.