Melanoacanthoma

Abstract
EM studies confirmed that melanoacanthoma is a nonnevoid elevated epithelial tumor composed of keratinocytes of basaloid and spinous differentiation and large dentritic melanocytes. The block in transfer of pigment from melanocytes to keratinocytes was not complete. Langerhans'' cells present in all malpighian layers were normal in morphology. Immunofluorescent studies and an immunoprecipitin also showed the patient''s melanoacanthoma not to be related to malignant melanoma.