Giant Coronary Artery Aneurysm with Thrombosis Complicated in a Patient with Idiopathic Hypereosinophilic Syndrome

Idiopathic hypereosinophilic syndrome (iHES) is a rare systemic disease that is characterized by persistent peripheral eosinophilia (absolute eosinophil count ≥1500/uL) for more than 6 months, with end-organ damage and absence of a primary cause for eosinophilia. Coronary artery aneurysm (CAA) is a rare but life-threatening complication. Here, we report a case of CAA with thrombosis in a patient with iHES in whom the disease activity was well-controlled (eosinophil count <500/uL) for several years. Despite modest control of the disease activity, giant CAA can be associated with iHES; and therefore, close surveillance and monitoring for the development of complications is warranted.