[Medullomyoblastoma: immunohistochemical and ultrastructural study]

Medullomyoblastoma is a rare tumor of childhood, arising in the cerebellar vermis. In the case reported, the immunohistochemical study (desmin, myosin, myoglobin and actin) and the ultrastructural findings, confirm the presence of rhabdomyoblastic cells associated with a typical medulloblastic component. Differential diagnosis and histogenesis of this tumor are discussed.