Idiopathic Hypereosinophilic Syndrome Associated with Multiple Intracardiac Thrombi

A 17‐year‐old man was referred for dyspnea, fatigue, and fever. Idiopathic hypereosinophilic syndrome was diagnosed. Transthoracic echocardiography demonstrated multiple intracardiac thrombi in the left ventricular apex. Dissolution of thrombi was not seen despite intensive medical therapy. The patient died because of cerebral embolus.