Melanotic Neuroectodermal Tumor of Infancy (MNTI) shows dual epithelioid and neuroblastic differentiation. In addition to the melanin-containing epithelioid cells, MNTI has nests and sheets of small, round blue neuroblastic cells (shown here) in a fibrillary background. These cells are positive for NSE, synaptophysin, and occasionally chromogranin. S-100 is negative in both epithelioid as well as neuroblastic cell populations. In some areas, one sees a single layer of epithelioid cells intimately associated with groups of neuroblastic cells.