CT of renal and perirenal non-Hodgkin lymphoma. 
The CT findings from a retrospective review of 16 patients (32 kidneys) with non-Hodgkin lymphoma involving the kidney are presented.  In all cases, computed tomography (CT) accurately depicted the presence, location, and size of the renal lesions and provided information about the adjacent retroperitoneum.  CT was helpful in evaluating the course of the disease and its response to therapy.  The CT manifestations of renal lymphoma included: solitary nodules (four kidneys), multiple nodules (nine), focal infiltration (five), diffuse infiltration (two), engulfment of the kidney by contiguous retroperitoneal disease (three), and renal enlargement (13 kidneys).  Bilateral renal involvement was noted in seven patients.  All 16 patients had retroperitoneal adenopathy.  The CT findings of intraparenchymal renal nodules, renal infiltration, or renal engulfment by retroperitoneal disease in association with retroperitoneal adenopathy should suggest the possible diagnosis of renal lymphoma.