Objective  To investigate the imaging findings of rare tumors or tumor-like lesions in liver grafts after liver transplantation.

  Methods  Imaging data of 4 patients with rare tumors or tumor-like lesions in the liver grafts of patients after liver transplantation from December 2006 to August 2013 in the Third Affiliated Hospital of Sun Yat-sen University were reviewed. Findings of computerized tomography (CT) and (or) magnetic resonance imaging (MRI) plain scan and dynamic enhanced MRI of liver lesions in these patients were analyzed specially.

  Results  In the 4 patients, 3 cases were misdiagnosed, including undifferentiated liver sarcoma, secondary lymphoma and eosinophilic granuloma. One case was diagnosed correctly with hepatic metastases of gallbladder carcinoma. The undifferentiated liver sarcomas appeared as cystic and solid space occupying masses with significant and persistent enhancement in the surrounding solid and separating parts. No enhancement was observed in the cystic parts, which increased rapidly in a short term. No edema area around the lesions was observed, but many calcifications were detected. The secondary hepatic lymphoma appeared as intrahepatic multiple nodules, most of which presented uniform signal intensity with moderate enhancement in every phase. No intrahepatic vascular invasion was observed but extrahepatic lymphadenectasis was detected. Bleeding was observed in a few lesions. The liver eosinophilic granuloma appeared as multiple liver lesions with variable signal intensity and enhancement modes, which suggested that the lesions were consisted of variety of elements and in the different disease stages. Most of the lesions were observed with progressive circled enhancement. The recurrence of gallbladder carcinoma and hepatic metastasis after liver transplantation appeared as a intrahepatic hypodensity lesion with slight enhancement in arterial phase and slight hypodensity in portal phase. Retroperitoneal lymph nodes were observed swelled and fused.

  Conclusions  Rare tumors or tumor-like lesions in liver grafts have distinctive imaging features. Imaging examinations are useful for the early detection of these rare tumors or tumor-like lesions in liver grafts. Imaging findings combining with disease history and clinical manifestations can help to make correct diagnosis.