A case of recurrent eccrine porocarcinoma

BACKGROUND: Eccrine porocarcinoma, first described in 1963, is a rare malignant lesion arising from the eccrine sweat glands. It is usually a primary tumor, even more commonly, a malignant degeneration of an eccrine poroma. It usually affects elderly, and is located commonly in the lower extremities. About 20% of the cases will reappear after treatment. The treatment consists of wide local excision of the primary lesion. This uncommon skin tumor is locally aggressive and has a high recurrence rate. CASE REPORT: We report a 95-year-old woman with a large tumor on the left knee. A large number of tumoral cells showed immunolabeling of p63 supporting squamous or myoepithelial differentiation. They were also positive for cytokeratin-7 (CK7), epithelial membrane antigen (EMA), and carcinoembryonic antigen (CEA) highlight luminal differentiation in some of the vacuolated cells and this was also seen with periodic acid-Schiff-diastase (PAS-diastase) staining. CONCLUSION: Eccrine porocarcinoma is a rare aggressive form of skin cancer with unknown etiology, and little guidance is available in the literature on exact protocols for treatment and follow up. It should be on the differential diagnosis of any suspicious skin lesion seen by the plastic surgeon. Histologic assessment is indicated in suspicious lesions.