Hypereosinophilic syndrome presenting with large left ventricular apical thrombus and pulmonary embolism.

A 45-year-old man presented with dyspnea on exertion, fatigue, and cough. Transthoracic echocardiography showed a large apical thrombus in the left ventricle. The laboratory results showed prominent eosinophilia on blood smear, elevated acute phase reactants and D-dimer serum levels. Bone marrow examination showed a Fip1-like platelet-derived growth factor receptor alfa fusion gene mutation. The case was diagnosed as myeloproliferative variant hypereosinophilic syndrome. Contrast-enhanced computed tomography demonstrated thrombi not only in left ventricle but also in multiple segmental pulmonary arteries. Cardiac magnetic resonance imaging showed left ventricular apical thrombus without subendocardial fibrosis. Cardiopulmonary manifestations of hypereosinophilic syndrome completely resolved after treatment.