Background: Second primary malignancies have been described in patients with both solid tumors and hematologic malignancies. However, an association between renal cell carcinoma and lymphoid malignancies has rarely 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 carcinoma, lymphoma, leukemia, or myeloma discharged from the University of California at Los Angeles between July 1, 1993 and June 30, 1995 was performed. Renal cell carcinoma was diagnosed in 186 patients, whereas 405 had a lymphoid malignancy. Eight patients with both disorders were identified.
Results: In four of the eight patients, the renal cell carcinoma was diagnosed prior to their hematologic malignancy, whereas in the remaining four patients, the lymphoid malignancy was diagnosed first. 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 renal 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 observed (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 explained by treatment-related development of a second malignancy. A common genetic mutation or an immunomodulatory role of the first malignancy predisposing to the second are possibilities but further investigation is warranted.