RESUMEN
Neuroblastoma is the third most common malignancy of childhood, after leukemia and brain tumors. Only 2% of all neuroblastoma occur in the brain. Primary cerebellar neuroblastoma is an specific subset of Primitive Neuroectodermal Tumors [PNET]. Meduloblastoma is a relatively common and well-established entity, consisting of primitive and multipotential cells that may exhibit some evidence of neuroblastic or gliad differentiation. But cerebellar neuroblastoma with ultrastractural evidence of significant neuroblastic differentiation is extremely rare. We report a rare case of neuroblastoma in the cerebellum. A 2.5-year-old Iranian boy presented with vomiting and nausea in the morning and ataxia. CT scan showed a tumor mass in the cerebellum and the report of radiologist was medulloblastoma. Light microscopic assay showed a small cell neoplasm with lobules of densely packed cells [lobulated pattern] and better differentiated cells. Neuron-Specific Enolase was positive. Pathologic diagnosis confirmed the existence of cerebellar neuroblastoma. Chemotherapy followed surgical removal. No relapse occurred 12 months after surgery