Malignant melanotic neuroectodermal tumor: light and electron microscopic study.

An 11-year-old white boy had a melanotic neuroectodermal tumor of infancy (MNTI) in his right mandible. Gross-examination showed that the tumor had originated in the right lower dental nerve, destroyed the right mandible, infiltrated the surrounding soft tissues, and metastasized to several lymph nodes. The typical alveolar pattern was observed in most of the tumor mass; however, solid areas with neuroblastic features were present in the infiltrating and metastasizing portions of the tumor. Ultrastructural study demonstrated unequivocal neuroblastic and melanocytic differentiation.