Malignant lymphoma of the kidney

Primary renal lymphoma (PRL) is a rare disease, making information including etiologic factors for PRL extremely limited.

Clinical and pathologic findings of PRL in Japan are presented and compared with those from Western countries. The presence of Epstein-Barr 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 fulfilled the following criteria: (1) presence of renal mass without extrarenal lymphomatous involvement at admission and (2) absence of a leukemic blood picture. For histologic and immunohistochemical studies, 10% formalin-fixed and paraffin-embedded histologic specimens were used. Presence of Epstein-Barr virus (EBV) genome was examined by polymerase chain reaction (PCR) and in situ hybridization (ISH).

There were five males and three females; age at admission ranged from 15 to 79 years (median 57 yr). Abdominal and/or flank pain were the most common presenting symptoms. No particular past history was present in any of the patients. Histologically, tumor cells in all cases showed a diffuse pattern of proliferation: large cell type in six cases, mixed cell type and small lymphocytic type in 1 each. Immunohistochemistry revealed B-cell nature of lymphoma cells in all cases. Neither PCR nor ISH showed the presence of EBV genome in any cases.

PRL is non-Hodgkin's lymphoma of predominantly large cell type with a B-cell immunophenotype. EBV etiology is unlikely in PRL.