LAUSR

BACKGROUND Reactive lymphoid hyperplasia (RLH) of the liver is a rare liver lesion. It is considered difficult to differentiate radiologically from hepatocellular carcinoma, metastatic liver tumor and other pathologies. CASE SUMMARY A 54-year-old woman presented to our hospital with RLH of the liver. The patient had a diagnosis of metastatic carcinoma of the liver from an unknown origin and subsequently underwent partial hepatectomy. However, histopathological analysis revealed RLH. The lesion showed perinodular enhancement in the arterial phase on contrast-enhanced computed tomography and magnetic resonance imaging. On diffusion-weighted imaging (DWI), we encountered linear hyperintensity along the portal tract consecutive to the liver lesion, which is a new characteristic radiologic finding. This finding corresponded to the lymphoid cell infiltration of the portal tract. Furthermore, there was strongly restricted diffusion on the apparent diffusion coefficient map. We used these characteristic radiologic findings to diagnose the lesion as a lymphoproliferative disease. CONCLUSION The linear hyperintensity consecutive to the liver lesion on DWI provided additional valuable diagnostic information.