MULTIFOCAL NEUROCYTOMA GANGLIOCYTOMA WITH EXTENSIVE LEPTOMENINGEAL DISSEMINATION IN THE BRAIN AND SPINAL-CORD/

This report describes an unusual neuronal tumor detected at the autops y of a 17-year-old boy. The tumor showed multifocal parenchymal involv ement with extensive leptomeningeal dissemination. The intraparenchyma l lesions were small and located mainly in the subpial region of the c erebrum, cerebellum and spinal cord. Leptomeningeal dissemination was particularly pronounced at the base of the brain and around the spinal cord and presumably took place during the relatively long clinical co urse. The tumor was composed of small round cells and ganglion-cell-li ke cells. Only neuronal differentiation, as represented by immunostain ing with antisynaptophysin antibody and the presence of dense-core ves icles in the cytoplasm, was evident in both types of cells. The small round cells appeared to exhibit the features of small, relatively matu re neurons rather than those of neuroblasts. Moreover, our results sug gested maturation from small round cells to ganglion-cell-like cells. The tumor appears to be related to gangliogliomas or dysembryoplastic neuroepithelial tumors, and we have chosen the term neurocytoma/gangli ocytoma for the unusual lesion.