MALIGNANT-LYMPHOMA OF THE KIDNEY

Background: Primary renal lymphoma (PRL) is a rare disease, making inf ormation including etiologic factors for PRL extremely limited. Method s: Clinical and pathologic findings of PRL in Japan are presented and compared with those from Western countries. The presence of Epstein-Pa rr virus (EBV) genomes in the tumor was also evaluated. Eight cases of PRL were collected from a review of the ''Annual of the Pathological Autopsy Cases in Japan (1976-1992)''. These cases fullfilled the follo wing criteria: (1) presence of renal mass without extrarenal lymphomat ous involvement at admission and (2) absence of a leukemic blood pictu re. For histologic and immunohistochemical studies, 10% formalin-fixed and paraffin-embedded histologic specimens were used. Presence of Eps tein-Barr virus (EBV) genome was examined by polymerase chain reaction (PCR) and in situ hybridization (ISH). Results: There were five males and three females; age at admission ranged from 15 to 79 years (media n 57 yr). Abdominal and/or flank pain were the most common presenting symptoms. No particular past history was present in any of the patient s. Histologically, tumor cells in all cases showed a diffuse pattern o f proliferation: large cell type in six cases, mixed cell type and sma ll lymphocytic type in 1 each. Immunohistochemistry revealed B-cell na ture of lymphoma cells in all cases. Neither PCR nor ISH showed the pr esence of EBV genome in any cases. Conclusions: PRL is non-Hodgkin's l ymphoma of predominantly large cell type with a B-cell immunophenotype . EBV etiology is unlikely in PRL. (C) 1997 Wiley-Liss, Inc.