Morphological investigations on cerebellar "neuroblastoma" group.

Classic medulloblastoma is a relatively common and distinct clinicopathologic entity consisting of primitive multipotential cells with differentiating capacity to neuroblastic and/or glial cell lines. Desmoplastic medulloblastoma has some features in common with cerebellar neuroblastoma, in which ultrastructural evidence of significant neuroblastic differentiation is extremely rare. We studied three cerebellar tumors with evidence of neuronal differentiation as compared to four classical desmoplastic medulloblastomas. Two of three tumors contained the regions of different degrees resembling desmoplastic medulloblastoma and one consisted of neuroblastic cells exclusively. This spectrum of differentiation suggests a relationship between cerebellar neuroblastoma and medulloblastoma, especially of the desmoplastic type. The nature of cerebellar neuroblastoma and its nosology are briefly discussed.