Large melanoacanthomas: a report of five cases.

Five patients with melanoacanthoma are reported. The skin lesions consisted of a single, round plaque measuring several centimeters in diameter. Histologic findings were characterized by formation within an acanthotic epidermis, of many islands of small basaloid cells and highly dendritic melanocytes. Electron microscopic examination of one lesion revealed a disturbance of melanin transfer from the highly dendritic melanocytes to the neighboring keratinocytes.