Case report of emergent embolization for ruptured internal thoracic artery pseudoaneurysm in a 42-year-old female

Internal thoracic artery (ITA) aneurysms are exceedingly rare vascular anomalies that often remain asymptomatic until rupture. Rupture can precipitate acute hemothorax, hemorrhagic shock, and death if not rapidly diagnosed and managed. We report the case of a 42-year-old previously healthy female who presented to the emergency department with sudden-onset chest, abdominal, and back pain. Initial CT imaging elsewhere revealed pleural effusion, a non-specific finding. Upon transfer to our institution, emergency computed tomography angiography (CTA) demonstrated a ruptured left ITA pseudoaneurysm with active contrast extravasation and a large left hemothorax. Emergent transcatheter arterial embolization using microcoils achieved definitive hemostasis. Ultrasound-guided chest tube drainage was subsequently performed. The patient recovered uneventfully and was discharged without complications. This case highlights a critical diagnostic pitfall in emergency medicine—ruptured ITA aneurysm masquerading as simple pleural effusion—and underscores the pivotal role of CTA and endovascular therapy in optimizing outcomes. We also review the literature on etiology, diagnostic challenges, and evolving therapeutic strategies for this rare but fatal condition.