Primary pilocytic astrocytoma of cerebello-pontine angle in the pediatric age group: literature review and case report.

Background: Primary pilocytic astrocytoma of the CPA (Cerebello-pontine angle), in the pediatric age group is an extremely rare entity, with just three cases reported so far. It mostly arises from the root entry zone of the cranial nerves found in this cistern. Case presentation: A 11-year boy presented with headache, hearing impairment in right ear. Pure tone audiogram and BAER (Brainstem auditory evoked response) suggested retro-cochlear sensori-neural hearing loss. MRI revealed a heterogeneously enhancing extra-axial lesion in the right CPA. Tumor was approached through right retromastoid suboccipital craniotomy. Intraoperatively it seemed to arise from the REZ (root entry zone) of CN VIII and histopathology confirmed it to be pilocytic astrocytoma. We have reported this as only the fourth case and reviewed the already existing literature. In the previous case reports an extensive immunohistochemical analysis was not done and the final diagnosis was not as per the Harlem consensus guidelines. Conclusion: In this case, we have tried to report the final histopathology in accordance with the 5th edition of WHO classification of CNS tumors. In the current era of molecular diagnosis and layered structural format of reporting a histopathology, this case is the first of its kind and emphasizes the need to consider PA as one of the differentials for lesions in CPA. [ABSTRACT FROM AUTHOR]