Objective: The purpose of this study was to describe unusual US and CT findings of eosinophilic infiltration in liver.
Methods: We retrospectively reviewed US and CT images of 60 nodules in 42 patients with eosinophilic infiltration in liver. Of 42 patients, 27 underwent both US and CT, and 15 only CT scans. Eosinophilic infiltration of liver was diagnosed by pathologically proven foci of eosinophilic infiltration(n=17) or suggestive clinical findings seen in combination with transient nature of lesions as they disappeared or partially regressed on follow-up imaging studies(n=25).
Results: Typical findings of eosinophilic infiltration are multiple, small, ill-defined hypoattenuating nodules which are most conspicuous on portal phase on CT, and small, ill-defined, hypoechoic nodules on US. Of 40 nodules, detected in 27 patients performed both US and CT, 22 showed typical US findings of eosinophilic infiltration, and 15 were not detected on US. Unusual US findings were peripheral hyperechoic rim(n=2) and slightly hyperechoic lesion(n=1). Of entire 60 nodules seen on CT, 52 demonstrated typical CT findings. Unusual CT findings were perilesional arterial enhancement(n=2), ill-defined hypoattenuating nodule on delayed phase with non-visualization on portal phase(n=2), discrete hypoattenuating nodule on portal phase(n=1), tubular shaped hypoattenuating nodule(n=1), ill-defined enhancing nodule on delayed phase(n=1).
Conclusion: Eosinophilic infiltration in liver with unusual imaging findings could be a mimic of metastasis, hepatocellular carcinoma or hemangioma. Unusual imaging findings of eosinophilic infiltration should be recognized, and eosinophilic infiltration should be included in differential diagnosis of unusual manifestation of focal hepatic lesion, especially in patients with peripheral eosinophilia.