摘要Background:Erythrocytosis,a rare paraneoplastic syndrome,generally occurs in patients with clear cell renal cell carcinoma and has never been reported in patients with chromophobe renal cell carcinoma.Case presentation:We report a case of a young man suffering from a giant (22-cm) mass on his left kidney.Because of a history of polycythemia vera,the patient had been treated for the condition for 9 years.Radical nephrectomy was successfully performed,and the postoperative pathologic examination confirmed a diagnosis ofchromophobe renal cell carcinoma.Unexpectedly,the symptom of erythrocytosis disappeared after the surgery.Further examination and analysis were performed,and we finally attributed his erythrocytosis to chromophobe renal cell carcinoma.Conclusions:Chromophobe renal cell carcinoma could cause erythrocytosis,but the clear-cut mechanism needs further research.Secondary erythrocytosis such as those related with renal tumors should be taken into consideration during the diagnosis of polycythemia vera.