[Renal lymphoma. Report of 2 cases and review of the literature].

Two cases of renal lymphoma were reported. Case 1 was a 73-year-old, and case 2 was a 59-year-old female. Their chief complaint was flank pain. The findings obtained by CT and angiography were not compatible with renal cancer. The tentative diagnosis of case 1 was inflammatory disease or soft tissue tumor, and that of case 2 was renal subcapsular tumor. Histological specimen was obtained by open biopsy from case 1, and by nephrectomy from case 2. Immunohistochemical surface marker study revealed both tumors were B cell lymphoma. Chemotherapy (CHOP-Bleo, or PPA) in both cases and additional radiotherapy in case 2 markedly reduced the tumor size. Nevertheless, case 1 died 5 months later from recurrence, and case 2 died 14 months later of gastrointestinal bleeding. At autopsy, the renal subcapsular layer was infiltrated by lymphoma cells in both cases, and lymphadenopathy was not observed. Reviewing 16 cases previously reported as renal lymphoma, the capsular or subcapsular diffuse infiltration to the kidney is considered to be a characteristic feature of renal lymphoma.