Embryonal tumor with abundant neuropil and true rosettes with melanotic (retinal) differentiation.

Embryonal tumor with abundant neuropil and true rosettes (ETANTR) is a rare variant of central nervous system primitive neuroectodermal tumor occurring exclusively in the pediatric population. We report a unique case of a 6-month male child presenting with a large intraventricular lesion. Histological examination revealed a tumor composed of primitive neuroectodermal cells in dense aggregates, interspersed by hypocellular areas containing small round cells widely dispersed in neuropil-like material. Few ependymal and occasional ependymoblastic rosettes were appreciated. Focal melanotic neuroepithelium recapitulating retinal differentiation was also seen. Documentation of such cases may expand the neuroectodermal differentiation spectrum of ETANTR.