Malignant clear cell hidradenoma: a case report and literature review.

Malignant clear cell hidradenoma is an uncommon variant of sweat gland tumors. Histological sections show lobulated masses and anastomising cords of cells which were polygonal to slightly fusiform in appearance. Most of the cells have bland appearing ovoid nuclei with slightly eosinophilic to clear cytoplasm. Focal areas within the lesion may show malignant changes. These areas may demonstrate large pleomorphic hyperchromatic nuclei, numerous mitotic figures, and a tendency toward squamous differentiation with many of the neoplastic cells demonstrating individual keratinization. Treatment is wide local resection. Consideration of regional lymph node dissection should be entertained because of the tendency to angiolymphatic spreads. Radiotherapy has not been shown to be helpful. Various chemotherapeutic regimens have been tried with inconclusive results. An illustrative case report is presented.