Epidermoid hidradenoma. A clinicopathologic study.

Clinical and histopathologic data in 8 cases of epidermoid hidradenoma are presented. Most of the tumors were in the head and neck, and most of the patients were middle-aged and older adults. Generally, the lesions were asymptomatic nodules that sometimes showed ulceration or rapid growth. Despite having some histologic atypia or focal mitotic activity, the tumors were found to be benign on long-term evaluation. This epidermoid variant should not be otherwise differentiated from the benign group of solid-cystic hydradenomas, because cytologic variability did not predict a significant change in prognosis.