The significance of immunocytochemical markers, synaptophysin and neurofilaments in diagnosis of ganglioglioma.

Ganglioglioma is a tumor composed of neoplastic neurons and neoplastic glial cells mixed in different proportions. Astrocytes are the essential glial component. The tumor proliferates mostly in the temporal lobe cortex, scarcely in other areas of the brain. In ganglioglioma the population of ganglionic neurons is very difficult to diagnose. In the last ten years, immunocytochemical reaction with synaptophysin and neurofilament protein (NFP) triad considered as neoplastic neuron markers seemed to differentiate neoplastic nerve cells from normal neurons occurring incidentally within neoplastic proliferation area. In our study, the reaction with synaptophysin and NFP was performed on fragments of normal frontal lobe, pons and cerebellum as well as on fragments of post-operation tumor diagnosed as ganglioglioma. A positive synaptophysin reaction was obtained on the surface of neoplastic neurons in gangliogliomas, as well as on the surface of normal neurons in the encephalon, cerebellum and pons. Both neoplastic and normal neurons and their processes showed the expression of neurofilaments protein triad. Thus, a positive reaction of neurons with synaptophysin and NFP seems to be nonpathognomic in the diagnosis of the neoplastic neuron population in gangliogliomas.