Intracranial extension of an eccrine porocarcinoma. Case report and review of the literature.

Eccrine porocarcinoma is a rare malignant tumor of the true sweat gland. It commonly presents in the lower extremities with lymphatic metastasis. The authors describe the clinical presentation, radiographic evidence, operative discoveries, and pathological findings in a patient with an eccrine porocarcinoma involving the soft tissue of the occiput, which had eroded through the cranium. A review of the literature failed to reveal any other such case. The discussion includes the epidemiology, pathogenesis, treatment, and outcome of eccrine porocarcinomas. The six reported cases of scalp eccrine tumors are reviewed.