Neurosarcomatous malignant melanoma arising in a neuroid giant congenital melanocytic nevus.

We report a case of neuroid giant congenital melanocytic nevus (GCMN) in which a malignant schwannomalike tumor developed. Literature review reveals that neurosarcomatous differentiation occurs among malignant tumors arising in GCMNs, apparently with greater incidence in those GCMNs showing benign neuroid differentiation. Although the differences between neuroid melanocytes and Schwann's cells may be more conceptual than real, we believe that the current tumor arising within a melanocytic nevus is likely of neuroid melanocytic origin and best designated as neurosarcomatous malignant melanoma.