Medulloblastoma with glial and rhabdomyoblastic differentiation. A myoglobin and glial fibrillary acidic protein immunohistochemical and ultrastructural study.

This is a report of an unusual, densely cellular, midcerebellar neoplasm in a seven-year-old boy. Although clinically consistent with a medulloblastoma, immunohistochemistry and electron microscopy demonstrated glial and rhabdomyoblastic differentiation in the tumor. We discuss the differential diagnosis of this tumor as it relates to glial differentiation in medulloblastomas and the myogenic potential of primitive neuroectoderm.