Extra-axial cerebello pontine angle medulloblastoma: A rare site of tumor
CC BY-NC-ND 4.0 · Indian J Med Paediatr Oncol 2011; 32(02): 123-124
DOI: DOI: 10.4103/0971-5851.89801
Article published online:
06 August 2021
© 2011. Indian Society of Medical and Paediatric Oncology. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/.)
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Medulloblastoma is a common tumor of the posterior fossa, representing 20–25% of all pediatric neoplasms.
The tumor often occurs in the cerebellar vermis and at the apex of the fourth ventricle.[1,2] There are only a few reported cases of cerebellopontine (CP)-angle medulloblastoma in the literature, with most being intra-axial. The extra-axial site of this tumor remains a rarity.[1,3]
This 4-year-old girl presented with left hemicranial headache followed by facial asymmetry with deviation of angle of mouth for 1 month. There was no other significant history.
On clinical examination, higher intellectual functions were normal, both pupils were equal and reacting to light, visual acuity/visual fields were normal, fundus-no papilloedema, left lower motor neuron facial paresis, and left-sided sensory neural hearing loss, other cranial nerves normal. No stigmata of neurofibromatosis was noted. A computerised tomography (CT) scan of the brain showed contrast enhancing extra-axial lesion in the left CP angle centered around internal acoustic meatus [Figure 1]. CT bone window did not show enlargement of the internal acoustic meatus or hyperostosis [Figure 1]. Magnetic resonance imaging (MRI) of the brain showed CP angle lesion which was hypointense on T1W and hyperintense on T2W image [Figure 2]. The lesion was brilliantly enhancing with contrast, and no dural tail or canalicular component noticed [Figure 3]. She underwent left retromastoid craniectomy and total excision of the lesion. It was grayish, moderately vascular, and soft. There was a clear plane between the tumor and cerebellum, whereas it was adherent to dura and tent laterally. The HPE was confirmed as desmoplastic medulloblastoma [Figure 4] with the high MIB-1 labeling index and S-100 negativity.