Hepatic pseudolymphoma with hepatobiliary-phase ring-like hyperintensity on gadoxetic acid-enhanced MRI: radiologic-pathologic correlation with intratumoral fibrosis.

Hepatic pseudolymphoma (HPL) is a rare benign lymphoproliferative disorder that can mimic malignant hepatic tumors on imaging. Hepatic pseudolymphoma is usually small and solitary; however, multiple lesions can develop in some cases. Herein, we report multiple HPLs with an unusual hepatobiliary finding on gadoxetic acid-enhanced MRI. A woman in her 50 s with non-alcoholic fatty liver disease was incidentally found to have 2 hepatic tumors: a 3-cm lesion in segment 5 (S5) and a 1-cm lesion in segment 8 (S8) during pre-operative cholelithiasis evaluation. The laboratory tests, including liver function and tumor marker levels, were unremarkable. The 2 lesions were hyperintense on fat-suppressed T2-weighted images and showed restricted diffusion. On dynamic gadoxetic acid-enhanced MRI, both lesions demonstrated faint arterial enhancement and hepatobiliary-phase hypointensity, with peritumoral arterial-phase hyperenhancement. Additionally, the S5 lesion showed faint linear hyperintensity adjacent to the lesion on diffusion-weighted imaging and contained an internal ring-like area that was hypointense on T2-weighted images but hyperintense within an otherwise hypointense lesion in the hepatobiliary phase. As malignancy could not be excluded, laparoscopic anterior sectionectomy was performed. Histopathological examination confirmed reactive lymphoid hyperplasia in both lesions. In the S5 lesion, the intratumoral fibrotic tissues formed a ring-like structure corresponding to the hepatobiliary-phase hyperintensity. Hepatobiliary-phase ring-like hyperintensity attributable to intratumoral fibrosis in HPL has not been previously reported. Awareness of this imaging-pathology correlation may improve interpretation of HPL imaging and help differentiate it from malignant hepatic tumors that can show hepatobiliary-phase hyperintensity, including hepatocellular carcinoma, cholangiocarcinoma, and metastases.