Pinealoblastoma with retinoblastomatous differentiation.

A case of primitive neuroectodermal tumour originating from pineal parenchymal cells in a 2 1/2-year-old boy is described. The tumour exhibited divergent lines of differentiation including neuroblastic and photoreceptor differentiation, thus aligning it with neuroblastomas and with retinoblastomas. The tumour recalls the function of the pineal as a photoreceptor organ at an earlier stage of its phylogenesis.