Primary renal non-Hodgkin's lymphoma: a clinicopathologic study of six cases and review of the literature

Primary renal lymphoma (PRL) is a rare disease and the information about pathogenesis, prognosis and treatment for PRL is extremely limited. We describe six patients primary appearing with symptoms or signs related to lymphoma predominantly or exclusively involving one kidney. The patients including two males and four females, aged at 55-73 years (median, 64 years). Two of them had other malignant lesion previously or simultaneously. Abdominal and/or flank pain were the most common symptoms. Five cases were initially considered to be primary carcinomas of the kidney on clinical evaluation, and the other one was diagnosed as hydronephrosis. The lymphomas were subclassified as diffuse large B-cell lymphoma (DLBCL, five cases) and small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL, one case). Extrarenal lesions were excluded by bone marrow aspiration or biopsy, thoracoabdominal computed tomography (CT) and positron-emission tomographic CT. According to the Ann Arbor system, four patients were diagnosed as stage IE non-Hodgkin's lymphoma (NHL); the other two were diagnosed as stage IIE. Radical nephrectomy was performed in four patients, and two of them subsequently received combination chemotherapy. The other two received chemotherapy immediately after kidney biopsy showing DLBCL. After a median follow-up time of 15.5 months (6 to 73 months), two patients were alive, and the other patients died from progressive disease 6 to 73 months after diagnosis. PRL is a rare disease with undefined etiology and pathogenesis, and there is no standardized treatment for it till now. According to our experience and other recently published studies, we hypothesize that early diagnosis combined with CHOP + rituximab could improve the prognosis of the patients.