Introduction Behçet’s disease is a multisystem inflammatory disease of unknown aetiology characterised by oral and genital ulceration, vascular lesions, and ocular, cutaneous and neurological manifestations. Many disease features are due to vasculitis and it is particular for its involvement of all sizes of blood vessels on both sides of the circulation.

Case report We present a report of a 43-year-old female with a background of severe neurological complications of Behçet’s disease (previous rhombencephalitis) presenting with left-sided headache, neck pain, photophobia, diplopia, nausea and vomiting. Complete left third nerve palsy developed during admission. MR brain imaging excluded acute parenchymal disease but was suggestive of a left posterior communicating artery aneurysm, confirmed on CT angiogram. Urgent catheter angiography demonstrated a 5×3 mm left anterior choroidal artery aneurysm, which was occluded by coiling. Two months later, left oculomotor nerve palsy had resolved and follow-up imaging at six months showed stable appearances.

Discussion Intracranial aneurysms are a rare but potentially life-threatening complication of Behçet’s disease. Intracranial aneurysms are potentially treatable and should be considered in Behçet’s patients presenting with intracranial pathology.