Concurrent posterior communicating and ophthalmic artery aneurysms in a teenager: diagnostic and endovascular management considerations.

Paediatric intracranial aneurysms are uncommon and often linked to congenital or developmental vascular anomalies. Their presentation can be subtle and may initially mimic benign conditions. We report the case of a mid-adolescent boy who presented with progressive headaches, blurry vision and new-onset left eyelid ptosis. Examination revealed a dilated, sluggish left pupil with impaired adduction and elevation, consistent with a cranial nerve III palsy. Although a non-contrast CT of the brain was normal, MR angiography identified a 6 mm lobulated, saccular aneurysm of the left internal carotid artery at the origin of the posterior communicating artery. Prompt endovascular treatment resulted in gradual neurological recovery. This case highlights the importance of recognising isolated cranial nerve III palsy as a potential marker of unruptured aneurysm in adolescents and emphasises the need for early vascular imaging.