Melanotic neuroectodermal tumor of infancy in the soft tissues of the arm: fine needle aspiration biopsy and histologic correlation-a case report.

A case of melanotic neuroectodermal tumor of infancy (MNTI) presenting as a soft tissue mass in the right arm of a 6-mo female child is discussed. The mass was diagnosed by fine-needle aspiration biopsy (FNAB) and confirmed by histological examination. This communication emphasizes the characteristic cytology of MNTI and discusses its significance in the context of this tumor occurring in the soft tissues. The cytology smears were distinctive in showing a dual population of small, rounded, undifferentiated cells and larger melanin-containing epithelial-like cells. It is the identification of the latter cells in the smears which differentiates this tumor from other round cell tumors of infancy and helps in the correct diagnosis by FNAB.