Successful treatment of erythropoietin-producing advanced renal cell carcinoma after targeted therapy using sunitinib: Case report and review of the literature.

In general, only ≤5% of patients with renal cell carcinoma (RCC) develop paraneoplastic erythropoietin (EPO) overproduction-induced polycythemia. However, a number of reports on EPO-producing RCC are available. The present study aimed to report the first case of a patient demonstrating a therapeutic effect on EPO-producing advanced RCC, subsequent to targeted pre-surgical sunitinib therapy, with a review of the literature. The patient involved was a 62-year-old male who presented with a malformation of the left scrotum. Examination revealed a tumor of 73 mm in diameter along with lymph node metastasis. The histological examination indicated a clear cell RCC containing viable cells as well as hemorrhage and necrosis. EPO in cancer cells was confirmed by immunohistochemistry. Subsequently, a case of EPO-producing RCC with polycythemia was diagnosed. The EPO-producing RCC was successfully treated following targeted presurgical therapy with sunitinib.