Renal involvement in lymphoma: prevalence and various patterns of involvement on abdominal CT

Objective The kidney is a frequent site of involvement in lymphoproliferative disorders. The aim of this study was to demonstrate the prevalence and spectrum of morphologic appearances of renal involvement in patients with lymphoma on helical computed tomographic (CT) scan. Methods Three phases of post-contrast helical CT of the abdomen in 74 patients with lymphoma were reviewed for possible renal involvement: the cortico-medullary, nephrographic and delayed excretory phases. Tumor characteristics, patterns of distribution and enhancement features were evaluated. Results Of the 74 patients with lymphoma, 11 had CT evidence of renal involvement-ten with non-Hodgkin's lymphoma and one with Hodgkin's lymphoma-representing 15% of all patients scanned for routine staging of histologically diagnosed lymphoma. Five types of renal involvement were observed: enlarged lobular non-enhancing kidneys (four patients); bilateral multiple renal masses (two patients); focal single non-enhancing mass (two patients); perirenal infiltrations from retroperitoneal extension (two patients); bilateral diffuse areas of non-enhancing hypo-densities (one patient). Conclusions Five distinct patterns of renal involvement with lymphoma were detected with helical CT. The most common appearance was enlarged lobular kidneys. CT with intravenous contrast enhancement is currently the approach of choice for both the evaluation of renal involvement as well as for accurate staging of lymphoma. Awareness of different patterns of renal involvement in lymphoma allows proper differentiation from other similar diseases.