Objective To explore the features of hepatic pseudolymphoma on diffusion weighted imaging (DWI) and dynamic contrast-enhancement magnetic resonance imaging (DCE-MRI).

Method The MRI findings of 22 lesions in 14 patients with hepatic pseudolymphoma confirmed by pathology in Zhongshan Hospital, Fudan University from February 2014 to February 2021 were retrospectively analyzed. The characteristics of MRI sequence signals and the characteristics of dynamic enhancement at each stage were qualitatively evaluated.

Result On MRI plain scan, the lesions were homogeneous, with obviously high signal on DWI and obviously low signal on apparent diffusion coefficient (ADC). The tissue around 15 lesions showed linear high signal along the portal area on DWI. Wedge-shaped signal changes in adjacent liver parenchyma extending from the lesion along portal vein were also observed on T₂WI and DWI in 3 lesions. After enhancement, 7 lesions had thick wall circular enhancement in arterial phase, the enhancement amplitude in portal vein and delayed phase was reduced, and the peripheral circular enhancement continued. 13 lesions were enhanced to varying degrees in the arterial phase, including 9 lesions with mild to moderate enhancement and 4 lesions with obvious enhancement, the central clearance in the portal phase and delayed phase, and the edge was still enhanced. Two lesions showed mild to moderate enhancement in arterial phase, and isointense in portal and delayed phases.

Conclusion Homogeneous signal, obvious restricted signal distribution and circular enhancement at different stages of DCE-MRI are specific signs of hepatic pseudolymphoma. Linear high DWI signal in the portal area around the lesion and wedge-shaped edema along the portal vein adjacent to the liver parenchyma are more helpful for the diagnosis of hepatic pseudolymphoma.