RESUMEN
Diffuse bilateral infiltration of the kidneys by lymphoma is probably the rarest cause of renal insufficiency. Moreover, acute renal failure as the initial manifestation of the lymphoma is reported only in a few cases. A 44-year-old man complaining of bilateral flank pain and weakness for 2 months was admitted with acute renal failure. Ultraonography revealed hyperechoic bilaterally enlarged kidneys and an enlarged spleen. Fat pad aspiration was negative for amyloidosis and serum protein electrophoresis was normal. Needle biopsy of the kidney and pathologic examination showed diffuse infiltration of the interstitium with lymphocytes and atypical cells. Bone marrow aspiration and biopsy were negative for malignant cells. Open kidney biopsy was performed and infiltrated cells positive for CD20 and negative for CD3 markers were observed based upon which diagnosis of diffuse large B-cell type non-Hodgkin lymphoma was made