Polar spongioblastoma: an immunohistochemical and electron microscopical study.

A case is reported of a 9-year-old boy with a cerebral polar spongioblastoma. This neoplasm, first described by Russell and Cairns in 1947, is morphologically a distinct entity characterized by bipolar tumor cells with palisading nuclei. In the case under study immunoreactivity for neuron-specific enolase was found and ultrastructural features of developing neuronal elements were present. A neuro-endocrine nature was suggested by de Chadarévian et al. (1984) in a morphologically similar case. These findings are in contrast with the long-held view that the polar spongioblastoma is cytogenetically related to the embryonal radial glial cells.