Adult intraventricular pilocytic astrocytoma: A case report highlighting its rarity with pathological insights

Pilocytic astrocytomas are WHO Grade 1 astrocytic tumours predominantly seen in children. Adult-onset and intraventricular pilocytic astrocytomas are exceedingly rare, often presenting unique diagnostic and therapeutic challenges. A 25-year-old female presented with a 6-month history of headache and a single seizure episode. MRI revealed a large, lobulated, predominantly solid mass with an eccentric cystic component occupying the fourth ventricle. The lesion demonstrated heterogeneous enhancement without calcification or haemorrhage. Gross total excision was performed via a midline suboccipital craniotomy. Intraoperative smears showed piloid cells, Rosenthal fibres, and eosinophilic granular bodies, suggestive of pilocytic astrocytoma. Histopathology confirmed the diagnosis. The postoperative course was uneventful, and the patient remains recurrence-free at 3 months follow-up. Intraventricular pilocytic astrocytomas in adults are extremely uncommon and may originate from adjacent parenchyma or aberrant astrocytic differentiation within the ventricular system. Surgical excision remains the mainstay of treatment; however, gross total resection can be limited by deep-seated location and proximity to vital structures. Molecular studies implicate MAPK pathway alterations, with KIAA1549-BRAF fusions common in paediatric PAs but less frequent in adults, who more often harbour BRAFV600E or FGFR1 mutations. These findings may guide emerging targeted therapies. Adult intraventricular pilocytic astrocytomas require a multidisciplinary approach for accurate diagnosis and management. Integration of clinical, radiological, histopathological, and molecular data is essential to optimize outcomes and explore novel therapeutic avenues.