Small cell malignant melanoma: an unusual morphologic variant.

Small cell melanoma is a recognized rare variant of malignant melanoma. We report a case of a brown, ulcerated papule on the left third finger of an 80-year-old woman. Microscopic examination revealed the presence within the epidermis of diffuse sheets of monomorphic small to medium-sized cells. The nuclei were round or oval, and hyperchromatic with inconspicuous nucleoli. Melanin pigment was either absent or minimal. This case report draws attention to the difficulties encountered in the histological diagnosis of this rare variant of malignant melanoma.