Primitive neuroectodermal tumor/Ewing sarcoma of the retina.

An 11-year-old boy underwent enucleation of his left eye for an intraocular tumor. Examination showed a small, round blue cell tumor arising in the peripheral retina near the ciliary body. Immunohistochemical stain results were positive for neuron-specific enolase, synaptophysin, cluster of differentiation 99 (CD99), Friend leukemia integration 1, and CD56. Ultrastructural findings included occasional intracytoplasmic dense core granules. Polymerase chain reaction of the tumor showed a Ewing sarcoma/Friend leukemia integration gene fusion product. The tumor was classified as a primitive neuroectodermal tumor/Ewing sarcoma of the retina and should be distinguished from retinoblastoma. To our knowledge, this is the first case of primary primitive neuroectodermal tumor of the retina.