Melanocytic neuroectodermal tumor of the foot. Report of a case with multicentric origin

This report describes a case of a two-year-old boy who had a tumor of the right fifth metatarsal. Biopsy revealed an undifferentiated, "small, round cell tumor" initially diagnosed as Ewing's sarcoma. He was treated with intensive chemotherapy, followed by amputation of the right foot when no response was observed. The histology of the amputated specimen was typical of melanocytic neuroectodermal tumor, a diagnosis confirmed by electron microscopy. Apart from documenting origin in a heretofore unrecorded site, this case illustrates the difficulties that arise in making a diagnosis and estimating prognosis of melanocytic neuroectodermal tumor, and provides evidence in favor of the multicentric origin of this uncommon disease.