MR imaging findings of hepatic pseudolymphoma: common and rare features

Purpose To summarize the common and rare MR imaging features of hepatic pseudolymphoma (HPL). Methods This retrospective study was approved by our institutional review board. 35 patients (mean age, 53.2 years) with 50 HPLs underwent enhanced MR. MR images were retrospectively reviewed and analyzed. Results There are 3 males and 32 females (8.6% vs 91.4%). 27 patients with single lesion and 8 patients with multiple lesions. Among the 50 HPLs, 90% of HPLs size ≤ 20mm, 92% were regular, and 92% were ill-defined. 7 and 5 patients had a history of malignant tumor and chronic liver disease. Tumor markers were negative in all patients. All 50 HPLs were low T1 SI, high T2 SI, high DWI SI, low ADC value, and adjacent to veins. 72% of HPLs were adjacent to the portal vein, 18% to the hepatic vein and 10% to the inferior vena cava. 72% of HPLs showed "linear sign" and "angular sign". There was a favorable agreement between "linear sign" and "angular sign" (kappa = 0.802, R < 0.001). 88% of HPLs showed “ring sign”. There were four enhancement patterns of HPLs (Table 2), wash out (46%), degressive (26%), persistent (18%) and progressive (10%). There were 2 patients with pathologically confirmed extra-hepatic pseudolymphomas. The largest HPL was 50mm in length with central cystic necrosis. Conclusions The common features of HPL are small, single, regular, adjacent to veins, low T1 SI, high T2 SI, high DWI SI and low ADC value. “Linear sign”, “angular sign” and “ring sign” could be seen as common features of HPL. The rare features of HPL included extra-hepatic lesion and central cystic necrosis.