Coexistence of multiple myeloma and clear cell renal cell carcinoma: a case report and review of literature.

Coexistence of multiple myeloma (MM) and renal cell carcinoma (RCC) is an extremely rare condition. Nevertheless, there is a higher than expected incidence of co-occurrence of these two malignancies. Several case series, in the recent past, have postulated an association between MM and RCC. Population-based data analyses have revealed a bi-directional association between these two malignancies. However, the cause still remains speculative up to date. Here, we aim to describe a patient with MM and clear cell renal cell carcinoma (CCRCC) one after another for the second time from China. Clinical implications are discussed with a critical review of existing literature and we expect to draw much more awareness among clinicians regarding such association.