Idiopathic hypereosinophilic syndrome with formation of multiple liver mass lesions

We report a case of idiopathic hypereosinophilic syndrome (IHES) characterized by multiple liver mass lesions in an 82-year-old man. Numerous hypoechoic lesions were observed on ultrasonography and were mainly distributed in the S4, S6, and S7 segments. Plain computed tomography (CT) scans revealed low-density lesions. Dynamic CT images revealed arterial and portal vein branches passing through these lesions, with marginal areas enhanced during the arterial phase. The enhanced areas were extended during the portal venous phase. Contrast-enhanced ultrasonography (CEUS) images revealed enhanced vasculature in the early vascular phase. CEUS images obtained in the late vascular phase revealed enhanced areas containing microbubbles extended into the parenchyma; a prolonged enhancement pattern was observed. Kupffer-phase images revealed large portions of the lesion filled with microbubbles and a star-like defect at the center of the nodule. F18-2-fluoro-2-deoxyglucose (FDG) positron emission tomography/CT scans revealed intense FDG uptake by these lesions, which was similar to that by the segments S4, S6, and S7. Liver biopsy revealed diffused eosinophils infiltrated. The patient was closely followed up and was completely cured 11 weeks later without any treatment. This is a rare case of IHES with multiple liver mass lesions, which was well researched using multi-imaging equipment and cured without any treatment.