MATH-1 production by an adult medulloblastoma suggestive of a cerebellar external granule cell precursor origin

Radiological, histological and molecular findings in an uncommon adult case of cerebellar medulloblastoma suggested an external granular cell precursor origin. This 19-year-old woman had a 1-month history of progressively worsening headache. Neuroimaging studies demonstrated a homogeneously enhanced well-circumscribed mass lesion in the right cerebellar hemisphere and she underwent surgery. Postoperative neuronal imaging studies showed that the tumor located in the cerebellar folia had been removed totally. Pathological examination identified it as a desmoplastic medulloblastoma with subpial and subarachnoid infiltration and some infiltration into the molecular and granular layer via the perivascular space. Polymerase chain reaction and immunohistochemical findings revealed the presence of MATH-1, expressed in cerebellar external granule cell precursors during fetal development, in the tumor cells. These findings suggest that the tumor arose from external granule cell precursors of the cerebellum and that it was therefore of neuronal lineage.