Atypical bilateral cerebellopontine angle medulloblastoma: differential diagnosis, immunohistochemical features and radiological presentation

Abstract

Medulloblastoma (MB) is a highly aggressive soft tissue neoplasm, classified as a primitive neuroectodermal tumor. It is the most common posterior fossa tumor in children, but occurs rarely in adults. MB accounts for approximately 20% of all primary central nervous system (CNS) tumors of childhood, while its incidence is around 1% of adult brain tumors. Most often it occurs in the cerebellum. We report a case of multicentric MB involving the bilateral cerebellopontine angle (CPA) and right cerebellar hemisphere. The tumor showed isointensity on T1/T2-weighted images, and slight hyperintensity on T2-weighted fluid-attenuated inversion-recovery (FLAIR) images. The MB had restricted diffusion on diffusion-weighted images (DWI). It was not easy to make an accurate diagnosis before biopsy. The lesion in our patient presented with atypical MR image features of medulloblastoma. To our knowledge, this is the first case of bilateral CPA MB.

Dural-Based Posterior Fossa Medulloblastoma Mimicking a Petrous Meningioma in Late Adulthood

“…Medulloblastoma of the posterior fossa is a common tumor in children but is rarely reported in adults, accounting for less than 1% of primary adult brain tumors. [1][2][3][4][5] This tumor can be characterized by location, histopathology, and the 2016 World Health Organization immunohistochemistry molecular grouping classification: WNT-activated, SHHactivated, group 3 and group 4. 6 In adults, posterior fossa medulloblastoma typically occurs before the age of 40 years, often exhibits classic histopathology, and tends to arise intra-axially within the cerebellar hemisphere.…”