Cerebellar "neuroblastoma": nosology as it relates to medulloblastoma.

Medulloblastoma is a relatively common and well-established entity, consisting of primitive, multipotential cells that may exhibit some evidence of neuroblastic or glial differentiation. However, cerebellar "neuroblastoma" with ultrastructural evidence of significant neuroblastic differentiation are extremely rare. We have studied three tumors with light microscopic evidence of neuroblastic differentiation. All of these tumors have regions resembling medulloblastoma; this finding suggests that cerebellar "neuroblastoma" represents one form of medulloblastoma. These cases provide further evidence for the potential medulloblastoma cells to differentiate along neuronal lines.