An association between renal cell carcinoma and multiple myeloma: a case series and clinical implications

OBJECTIVE To describe an association between renal cell carcinoma (RCC) and multiple myeloma (MM) in patients with both disorders, and suggest possible explanations for the association. PATIENTS AND METHODS We retrospectively reviewed the records of patients with MM and RCC at the Cleveland Clinic between 1990 and 2005, and identified 1100 with MM, 2704 with RCC and eight with concomitant MM and RCC. The medical records of these eight patients were reviewed. RESULTS In four of the eight patients, RCC was diagnosed after the MM at 3, 8, 23 and 46 months, respectively; in the remaining four, the RCC was diagnosed before MM by 108, 35, 13 and 1 months, respectively. The number of cases of RCC expected in the present 1100 patients with MM over 15 years was lower than the four recorded (P