Retinoblastoma--a histologic and immunohistologic study.

Histopathology and various immunohistochemical markers were studied in 40 cases of human retinoblastoma. In histopathology, tumour type, extent and invasion were studied. In immunohistochemistry, both glial and neural markers were used to know the histogenesis of this tumour. The glial markers, glial fibrillary acidic protein and vimentin, were detected in retinal astrocytes and Muller's cells in normal retina and perivascular glia in retinoblastoma. The neural marker, neurone-specific enolase stained neurones in outer and inner nuclear layers in normal retina, Flexner-Wintersteiner rosettes in retinoblastoma and tumour cells is differentiated retinoblastoma. Another neural marker, neurofilament triplet polypeptide stained neurones in inner nuclear layer of normal retina and Flexner-Wintersteiner rosettes in well-differentiated retinoblastoma. These results support the view that retinoblastoma has predominantly neuronal origin.