The incidence of lymphomas, has shown a steady increase over the last decades. The kidney is one of the most important solid organ affected by direct or indirect lymphomatous involvement. Kidney involvement can be related to obstruction or treatment-induced toxicity, but more intriguing are 1) direct infiltration 2) association with kidney malignancies 3) association with glomerular diseases.

In August 2009 a 72-year-old Caucasian man was admitted to a local hospital for fatigue and weight loss. It was found hypoalbuminemia and proteinuria in nephrotic range, mild renal failure, normochromic-normocytic anemia and thrombocytopenia. Physical examination, TC scan (Fig. 1a-1b) and ultrasonography showed splenomegaly, pleural effusion, edema in the lower extremities, latero-cervical, axillary, ilo-mediastinic, abdominal lymphadenopathy and increased dimensions of kidneys with changed parenchymal echogenicity. He was carried out axillary lymphonode biopsy with diagnosis of non-necrotizing granulomatous process with epithelioid cells and rare giant cells and bone marrow aspiration with diagnosis of B lymphoproliferative process. The search of amyloid in abdominal fat and immunological and virological screening resulted negative. The search of tumor markers and monoclonal paraprotein was negative. In October 2009 because of partial response to steroidal, albumin and diuretic therapy and worsening of renal function, the patient began haemodialysis treatment with regression of dyspnea and significant reduction of pleural effusion and legs oedema. In November 2009 it was possible perform renal biopsy with evidence of lymphoproliferative process. Histologically, the normal kidney architecture was extensively replaced by lymphoma with a diffuse pattern (Fig. 2-3a-3b). The neoplasm was composed predominantly of small lymphoid cells with mildly irregular nuclear contours and moderate cytoplasm. The neoplastic cells were CD20+, CD5-, CD10- and CD23. We made diagnosis of marginal lymphoma stage IV°.

Following CVP chemotherapy (cyclophosphamide, vincristine, prednisone) his renal function gradually improved and it was possible to stop dialysis. The creatinine fell to 132 µmol/l and the nephrotic syndrome was in remission (albumen 31 g/l).