Flow diversion of a distal M3 segment middle cerebral artery pseudoaneurysm in a pediatric patient: illustrative case.

backgroundIntracranial pseudoaneurysms are a rare yet treacherous subtype of cerebral aneurysms associated with a high risk of rupture. Left untreated, these lesions exhibit high rates of morbidity and mortality.The advent of flow diversion has shifted the treatment paradigm of these lesions from vessel sacrifice to vessel reconstruction. However, experience with flow diversion of distal intracranial pseudoaneurysms remains limited. OBSERVATIONS: A 14-year-old female was found to have a distal M3 segment middle cerebral artery pseudoaneurysm on routine noninvasive follow-up imaging following resection of a pleomorphic xanthoastrocytoma. Diagnostic cerebral angiography confirmed the presence of an 8-mm pseudoaneurysm in the distal left M3 middle cerebral artery. Flow diversion of the parent vessel was performed with a Pipeline Vantage embolization device. Completion angiography demonstrated early contrast stasis within the pseudoaneurysm with excellent wall apposition of the flow diverter. The patient tolerated the procedure well and was discharged on aspirin and ticagrelor for 6 months. LESSONS: Intracranial lesions suspicious for pseudoaneurysms on noninvasive imaging should be evaluated with diagnostic cerebral angiography. Intradural pseudoaneurysms are challenging lesions to treat with open cerebrovascular and endovascular approaches. Flow diversion of distal M3 middle cerebral artery pseudoaneurysms is a safe, feasible, and efficacious treatment option for these rare lesions. https://thejns.org/doi/10.3171/CASE25989.