Posterior fossa medulloblastoma in an atypical extra-axial location: A case report

Abstract

Medulloblastoma is the most common posterior fossa tumor of childhood typically within the fourth ventricle. However, extra-axial medulloblastoma in posterior fossa is an uncommon diagnosis. We report a case in a 33-month-old male who presented with repeated complaints of abdominal pain, intermittent emesis, and diarrhea, and diagnosed with right cerebellar extra-axial medulloblastoma, which was surgically resected. Majority of the reported extra-axial medulloblastoma in posterior fossa in the United States are located in the cerebellopontine angle. However, to the best of our knowledge, our case is the first to document medulloblastoma occurring exclusively in the cerebellar hemispheric extra-axial space rather than the cerebellopontine angle. Although the diagnosis can present as a radiological dilemma, a systematic multimodality imaging approach can aid in narrowing the differential diagnosis and timely management. In this case report, we will discuss the imaging characteristics, differential diagnosis, and management strategies, alongside a brief review of the world literature of extra-axial medulloblastoma.

Extraaxial cerebellopontine angle medulloblastoma with multiple intracranial metastases in adult: A rare case report with a review of literature

“…has suggested that extraaxial findings of MB are very rare in children, but nearly 50% of adult MBs arise from the cerebellum or pons at its lateral surface. [ 4 ] In our patient, the tumor was completely separated from the surrounding cerebellum and it was also extra-axial making it quite rare. The tumors most often occur among patients in their late 20s and early 30s.…”

“…It shows multiple flow voids in MRI due to hypervascular nature and generally associated with Von Hippel–Lindau syndrome. [ 4 ]…”

Medulloblastoma in the cerebellopontine angle mimicking a schwannoma

“…Unfortunately, CPA medulloblastoma may not have clear clinical and radiological characteristics that fully differentiate this neoplasm with other CPA tumors such as cholesteatoma, epidermoid, meningioma, and schwannoma 3,6‐11 . Furthermore, if a patient with CPA medulloblastoma experiences deafness, as was the case here, it is very difficult to distinguish CPA medulloblastoma from acoustic schwannoma.…”

“…Most medulloblastomas develop in the cerebellar midline at inferior vermis and typically expand into and occupy the fourth ventricle. A lower proportion of medulloblastomas are situated in the cerebellar hemispheres in adults 6‐11 . Medulloblastomas usually induce intracranial hypertension and cerebellar dysfunction in both children and adults 5 .…”

“…Medulloblastomas usually induce intracranial hypertension and cerebellar dysfunction in both children and adults 5 . Medulloblastomas are most commonly found extra‐axially in two areas: the tentorial region and CPA 6‐11 …”