CT of abdominal lymphoma after renal transplantation.

Six patients aged 33-68 years developed posttransplant lymphoma of the abdomen an average of 105 months after successful renal transplantation. On computed tomography (CT), five lymphomas presented as bulky masses in intra- (four) or retroperitoneal (one) location. Infiltrative growth into transplanted kidney (three), colon (two), and retroperitoneum (one) resulted in poorly defined margins on CT. Central areas of lower attenuation presumably reflected tumor necrosis. Metastatic deposits in liver (two) and renal transplant (one) were of a focal nature. Prompt radiologic recognition of this serious late complication of renal transplantation is crucial.