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Medullomyoblastoma is a highly malignant, bimodal embryonal tumor of the cerebellum characterized by a neuroepithelial and striated muscle component. Medullomyeloblastoma corresponds to WHO Grade IV.
The age distribution and clinical behavior of medullomyoblastoma mirrors those of childhood medulloblastoma, suggesting that medullomyoblastoma may be a variant of medulloblastoma.
Medullomyeloblastoma is a tumor of the cerebellar vermis.
Patients present with cerebellar signs and with signs and symptoms of raised intracranial pressure and hydrocephalus.
On MRI, medullomyeloblastomas appear as heterogeneously enhancing, irregular mass lesions arising in the posterior fossa. Non-invasive imaging does not distinguish between medullomyeloblastoma and medulloblastoma.
Medullomyeloblastomas are soft, moderately vascular tumors with variable degrees of necrosis.
The histopathologic appearance of medullomyeloblastoma is of a medulloblastoma with focal areas of myogenic differentiation. The myogenic component consists of bundles of striated muscle fibers, occasionally collected around tumor vessels.
The biologic behavior of medullomyoblatoma mirrors that of medulloblastoma.