[Immunohistochemical study of subependymal giant cell tumor associated with tuberous sclerosis]

Subependymal giant cell tumors from four patients associated with tuberous sclerosis were examined by peroxidase antiperoxidase (PAP) immunohistochemistry for neuron specific enolase (NSE), glial fibrillary acidic protein (GFAP) and S-100 protein. The tumor cells were grouped into three morphological types: ganglion-like pyramidal cells, swollen gemistocytic cells and fibrillated spindle cells. There was little difference in immunohistochemical property between these cell types in each case, suggesting that the tumor cells of different cell types have a same origin. The majority of the tumor cells was intensely stained for NSE in every case. On the other hand, for GFAP none of the tumor cells was stained in two cases, and the minority was weakly stained in the other two cases. The intensity of staining of the tumor cells for S-100 protein varied from case to case. Our findings together with those of others show the definite immunohistochemical characteristics of subependymal giant cell tumors with tuberous sclerosis, i.e., strong positivity for NSE in contrast to their negativity or weak positivity for GFAP. However, these findings do not necessarily suggest that the tumor is of neuronal origin, because in the case of neoplasms the significance of the presence of NSE as indicative of neuronal origin is open to question.