Poorly Differentiated Metastatic Carcinoma of Possible Eccrine Sweat Gland Origin

Sweat gland carcinomas are a rare group of cancer, representing less than .01% of all diagnosed skin malignancies. We report the case of a 32-year-old male who presented with a fungating lesion on the posterolateral side of his left knee. Immunohistochemical results were positive for cytokeratin 5/6 and cytokeratin 7, consistent with possible eccrine gland origin. Our patient underwent wide local excision of the mass with lymph node dissection. Pathology confirmed the diagnosis of poorly differentiated carcinoma of possible adnexal, eccrine gland origin. He completed taxol/cisplatin-based chemotherapy and radiation. Surveillance imaging showed bilateral lung nodules, a right pleural effusion, and peritoneal carcinomatosis, which were diagnostic of metastatic carcinoma. He started carboplatin and epirubicin chemotherapy and has been doing well. Because standard of care treatment options for metastatic eccrine carcinoma have not been developed, it is imperative to report these cases to better understand these complex tumors and their treatment.