Renal cell carcinoma and plasma cell myeloma: Unique association and clinical implications

Several case series, in the recent past, have postulated an association between plasma cell myeloma (MM) and renal cell carcinoma (RCC). Population-based data have revealed a bi-directional association between these two malignancies, which points to shared risk factors, similar cytokine (Interleukin-6, IL-6) requirements for growth and survival, and overlapping clinical presentation. The presence of lytic lesions in a patient with prior RCC may simulate bone metastasis; thus, leading to a diagnostic pitfall with potentially adverse clinical implications. Besides these, therapeutic strategies employed for MM have been tried for RCCs with partial success. We aimed to describe two patients, aged 64 and 54 years, with RCC-MM association, with review of relevant literature; and create awareness among pathologists/hematologists, and oncologists. Elucidating a common genetic basis might throw some light in understanding the pathobiology of these tumors and development of newer targeted therapies.