Cerebellar Pilocytic Astrocytoma Presenting with Obstructive Hydrocephalus in an Adolescent: A Case Report

Abstract

Background Pilocytic astrocytoma is a circumscribed central nervous system glioma classified as CNS WHO grade 1 and is one of the most common pediatric brain tumors. Cerebellar pilocytic astrocytomas may produce symptoms of increased intracranial pressure and cerebellar dysfunction, particularly when compression of the fourth ventricle results in obstructive hydrocephalus. Case Presentation A 15-year-old right-handed male patient presented with holocranial headache, projectile vomiting, gait disturbance, and progressive cerebellar dysfunction. Neurological examination revealed drowsiness, mixed appendicular and truncal ataxia, dysdiadochokinesia, nystagmus, and intention tremor. Non-contrast computed tomography demonstrated a 3 × 3 cm cystic and nodular lesion in the right cerebellar hemisphere, producing mass effect on the fourth ventricle, dilatation of the ventricular system, and periventricular edema. The Evans index was 0.40, and the third ventricle measured 1.6 cm. Emergency ventriculoperitoneal shunt placement was initially performed to treat the obstructive hydrocephalus. Subsequently, the patient underwent bilateral posterior fossa craniectomy, evacuation of the cystic component, and complete removal of the mural tumor nodule. Histopathological examination demonstrated pilocytic astrocytoma, CNS WHO grade 1. Outcome The postoperative course was favorable, and the patient was discharged 15 days after surgery. Follow-up cranial CT performed one year after surgery showed no evidence of tumor recurrence. At the most recent clinical follow-up, the patient was attending school normally and participating in regular academic activities without functional limitations or significant neurological disability. Conclusion Cerebellar pilocytic astrocytoma may present with significant obstructive hydrocephalus despite its generally indolent biological behavior. Prompt management of hydrocephalus followed by maximal safe tumor resection can result in favorable neurological and functional outcomes. Long-term clinical and radiological surveillance remains essential.