Melanotic Neuroectodermal Tumor of Infancy
Melanotic Neuroectodermal Tumor of Infancy (MNTI) shows dual epithelioid and neuroblastic differentiation. It consists of a population of larger polygonal to cuboidal epithelioid cells (shown here) forming nests, trabeculae, or pseudoglandular arrangements in a fibrous stroma. They have varying amounts of melanin pigment and are positive for keratin, HMB-45, and tyrosinase. Ultrastructurally, they show features of epithelial and melanocytic cells containing both immature and mature melanosomes.