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.

Cinnamomi Ramulus and Alismatis Rhizoma are commonly used in the treatment of external-contraction diseases. Cinnamomi Ramulus is pungent， sweet， and warm， with the effects of ventilating lung and dispersing cold， warming Yang and transforming Qi， and promoting water and liquid flow from Taiyang meridian to remove dampness. Alismatis Rhizoma is sweet and cold， with the effects of draining dampness and promoting urination， regulating the waterway， removing water retention in lung， and promoting urination to remove dampness and heat. Herbal pairs are extracted from the accumulated experience of medical practitioners over the ages in the use of medicines and have been proved by clinical application to be composed of simple and effective combinations for specific diseases. The herb pair Cinnamomi Ramulus-Alismatis Rhizoma is an important part in ancient classic formulas such as Wulingsan. Both herbs play a role in draining dampness and promoting urination， warming Yang and transforming Qi， being a representative herb pair used for treating external-contraction exterior syndrome and water retention inside. The review of ancient medical publications revealed that there were a large number of compound formulas containing Cinnamomi Ramulus-Alismatis Rhizoma for dispersing cold and removing dampness， which were widely used for thousands of years in clinical practice. Modern pharmacological studies have shown that the active pharmacological components of Cinnamomi Ramulus （cinnamaldehyde and cinnamic acid） and Alismatis Rhizoma （alisol A and 23-acetate alisol B） have anti-inflammatory， antiviral， and immunoregulatory effects and high safety. Qingfei Paidu decoction containing this herbal pair played an important role in fighting against COVID-19. Despite the extensive pharmacological studies on Cinnamomi Ramulus and Alismatis Rhizoma， few studies have been carried out regarding this herb pair. This paper summarizes the traditional Chinese medicine knowledge about Cinnamomi Ramulus and Alismatis Rhizoma in the treatment of external-contraction diseases and summarizes the chemical composition， pharmacological effects， toxicology and other aspects of the two herbs before and after compatibility， aiming to provide a reference for further research and clinical application.