Extra-axial Cerebellopontine Angle Adult Medulloblastoma: An Unusual Presentation at an Unusual Site

Abstract

Medulloblastoma is a rare adult primary brain tumor and its presence in the cerebellopontine angle (CPA) constitutes an even rarer site for origin. There are only 40 reported cases of CPA medulloblastoma in the literature, with most being intra-axial and occurring in the pediatric population. Extra-axial CPA medulloblastoma in adults are extremely rare and only 10 adult cases have been reported in world literature.We report a rare case of primary extra-axial CPA medulloblastoma occurring in an adult. We review the literature for such an unusual presentation of medulloblastoma in adults and discuss its appropriate clinico-radiological features along with its possible pathogenesis and surgical management.With increasing reporting of such tumors, CPA region, medulloblastoma should be considered a differential diagnosis of intra-axial or extra-axial CPA tumor, as their further management and prognosis differ significantly. Adjuvant radiotherapy and combined chemotherapy regimen should be added to the postoperative management.

Extra-axial desmoplastic medulloblastoma in adult cerebellopontine angle: Case report and noninvasive molecular subgrouping utilizing magnetic resonance imaging-based radiomics nomogram

“…There have been only 12 reported cases of extra-axial MB in the adult literature [ Table 1 ]. [ 2 4 5 6 7 8 9 10 11 12 13 ]…”

“…There have been only 12 reported cases of extra-axial MB in the adult literature [Table 1]. [2,[4][5][6][7][8][9][10][11][12][13] A review of all reported cases shows that CPA MB is twice more common in males in their 2 nd -3 rd decade, with the classic variety seen in more than half of the cases. Ten out of 12 reports so far published considered meningioma as a provisional diagnosis based on broad tentorial attachment, despite heterogeneous enhancement.…”

“…Wide/no Classic TE, RT -Furtado et al, 2009 [9] 32 male Moderate/heterogeneous Wide/no Classic TE, CT, RT -Singh et al, 2011 [10] 21 male Nonenhancing on CT/MRI not mentioned Wide/no Classic TE only 15 months/+/spinal mets (IM cervical, IDEM sacral) Spina et al, 2013 [11] 22 male Moderate/heterogeneous Wide/no Classic TE, RT −/no recurrence/M0 Spina et al, 2013 [11] 26 female Intense/homogeneous Wide/no Classic TE, RT −/no recurrence/M0 Bahrami et al, 2014 [12] 23 male Moderate/heterogeneous Wide/no Desmoplastic TE, RT 12 months Goudihalli et al, 2018 [13] 50 male Moderate/heterogeneous No/yes Classic PE Vegetative/died Ratha et al, 2019 [2] 42 female Moderate/heterogeneous Wide/no Classic TE, RT 15 months…”

“…[ 1 ] Cerebellopontine angle (CPA) is an atypical site for MB with 42 cases reported in both pediatric and adult population, intra- and extraaxial locations combined. [ 2 ] Extraaxially, the tumors have been localized in two areas: the tentorial region and the CPA. [ 3 ] In adults, only 12 cases were found in extra-axial CPA location.…”

“…[3] In adults, only 12 cases were found in extra-axial CPA location. [2,[4][5][6][7][8][9][10][11][12][13] Here, we report the 13 th case of an extra-axial lesion in the CPA of a 27-year-old male, which was presumed to be meningioma on preoperative imaging but turned out to be desmoplastic MB.…”