Clear Cell Variant of Eccrine Porocarcinoma of the Hand: A Case Report

In a case report from September 2018, a 90-year-old woman presented with a three-year history of a painful lesion on her left hand, which had rapidly grown over the past year. Clinical examination revealed a 4 x 4 cm exophytic, sharply bordered, erythematous, and erosive plaque on the dorsum of her hand. Suspecting malignancy, a wide surgical excision was performed. Histological analysis showed a polypoid neoplasia with clear cell changes, infiltrating the dermis and forming cords and tumor nests with necrosis. The neoplastic cells had hyperchromatic, pleomorphic nuclei with numerous mitotic figures and were positive for periodic acid-Schiff (PAS), epithelial membrane antigen (EMA), and carcinoembryonic antigen (CEA) staining. The patient remained lesion-free two years post-excision. This case represents a rare instance of clear cell eccrine porocarcinoma, a very rare cutaneous malignancy with aggressive potential, including frequent local recurrences, lymph node metastases, and occasional distant metastases. The treatment of choice is extensive surgical excision, as metastatic porocarcinoma is highly resistant to chemotherapy or radiotherapy and has a high mortality rate. This case is reported to be the third of its kind concerning clear cell changes in eccrine porocarcinoma.