AN ASSOCIATION BETWEEN RENAL-CELL CARCINOMA AND LYMPHOID MALIGNANCIES- A CASE SERIES OF 8 PATIENTS

BACKGROUND. Second primary malignancies have been described in patient s with both solid tumors and hematologic malignancies. However, an ass ociation between renal cell carcinoma and lymphoid malignancies has ra rely been described. Eight patients with both disorders are described and possible explanations for the association are reviewed. METHODS. A retrospective review of records from patients with renal cell carcino ma, lymphoma, leukemia, or myeloma discharged from the University of C alifornia at Los Angeles between July 1, 1993 and June 30, 1995 was pe rformed. Renal cell carcinoma was diagnosed in 186 patients, whereas 4 05 had a lymphoid malignancy. Eight patients with both disorders were identified. RESULTS. In four of the eight patients, the renal cell car cinoma was diagnosed prior to their hematologic malignancy, whereas in the remaining four patients, the lymphoid malignancy was diagnosed fi rst. Renal cell carcinoma is observed in the general population in 12. 5 persons per 100,000 and hematologic malignancies in 31.8 per 100,000 . The number of cases of lymphoid malignancies expected in the 186 ren al cell carcinoma patients is lower than the 4 cases actually observed (P < 0.01). Likewise, the number of renal tumors expected in the 405 patients with hematologic malignancies is fewer than the 4 cases obser ved (P < 0.01). CONCLUSIONS, The incidence of renal cell carcinoma and lymphoid malignancy occurring in the same patient is higher than that expected in the general population. This association cannot be explai ned by treatment-related development of a second malignancy. A common genetic mutation or an immunomodulatory role of the first malignancy p redisposing to the second are possibilities but further investigation is warranted. (C) 1996 American Cancer Society.