Rapid development of a posterior communicating artery aneurysm presenting with painful ophthalmoplegia

초록

Purpose: To report a rare case of rapidly developing posterior communicating artery (Pcom) aneurysm causing painful oculomotor nerve palsy, and to emphasize the importance of prompt neurovascular imaging in such presentations. Methods: A 77-year-old male with hypertension, hyperlipidemia, history of aortic valve replacement, and warfarin use developed acute-onset headache and left periorbital pain, followed by ptosis and ophthalmoplegia. Neurological examination revealed complete left third nerve palsy with anisocoria (3 mm vs. 2 mm), suggestive of parasympathetic fiber involvement. MRA performed one year earlier showed no aneurysm. Although Tolosa-Hunt syndrome was initially suspected, the pupil-involving nature raised concern for aneurysmal compression or other structural lesion. Orbital MRI, repeat MRA, and transfemoral cerebral angiography (TFCA) were conducted. Results: Imaging revealed a newly developed 3 mm left Pcom aneurysm with features suggestive of impending rupture. Coil embolization was promptly performed. The patient reported rapid pain relief and gradual improvement in oculomotor function. Conclusion: This case highlights the possibility of de novo aneurysm formation and rapid growth, even within a year. Painful oculomotor nerve palsy with pupillary involvement should raise suspicion for compressive aneurysm and warrants urgent vascular imaging. Early diagnosis and endovascular intervention can prevent catastrophic rupture and facilitate neurological recovery.