An immunohistopathologic study of trilateral retinoblastoma.

We examined retinal and midline pineal tumors from four patients with trilateral retinoblastoma who had antibodies against neural-associated antigens including neuron-specific enolase, photoreceptor cell proteins (S-antigen and rhodopsin), and glial fibrillary acidic protein. Expression of neuron-specific enolase was observed in all four patients. S-antigen immunoreactivity was present in three of four ocular tumors and two of four pineal tumors examined, whereas results of labeling with rhodopsin and glial fibrillary acidic protein were negative in each of the ocular and pineal tumors.