Objective:This study aims to investigate the clinicopathological features of paraganglioma of the bladder and the expression of succinate dehyrogenase B(SDHB),EPAS1 and Ki-67 in pheochromocytoma of the bladder,and its significance for predicting the clinical malignant behavior. Methods:The clinical and pathological data of 43 patients with cystoparaglioma admitted to our hospital were retrospectively analyzed,and the immunohistochemical tests of SDHB,EPAS1,CgA and Ki-67 were performed on 43 samples,and their significance as indicators for the prediction of malignant paraglioma was analyzed. Results:There were 43 cases of bladder paraganglioma in 19 females and 24 males. Ages 26-81,median age 68. The follow-up time was 2-84 months,with a median follow-up time of 51.3 months. There were 3 deaths,9 cases with postoperative metastasis,and 4 cases with recurrent recurrence without metastasis. The rest had no recurrence or metastasis. Microscopically,the neoplastic cells in 30 patients presented classic nest-like arrangement,with rare nuclear division and necrosis,and supporting cells surrounding the nests of neoplastic cells. SDHB expression was negative(-)in 4 cases,EPAS1 expression was strongly positive(+++)in 14 cases,CgA expression was strongly positive(+++)in 18 cases,and Ki-67 expression was ≥3% in 2 cases. Microscopically,there were 13 cases of malignancy. The tumor cells showed diffuse invasive growth or large nests,and nuclear division was common. Neoplastic necrosis and intrascularly neoplastic thrombus were seen. SDHB expression was negative(-)in 8 cases,EPAS1 expression was strong positive(+++)in 9 cases. There were 10 cases with strong positive CgA(+++) expression,11 cases with Ki-67 ≥3%. Among the SDHB negative tumors,66.7% was malignant,and among the SDHB positive tumors,16.1% was malignant. The difference between the two groups was statistically significant(P < 0.05). The expression intensity of EPAS1 and CgA and the proportion of Ki-67 ≥3% in SDHB negative tumors were significantly higher than that in SDHB positive tumors. The positive expression rates of EPAS1,CgA and Ki-67 in malignant cystoparaglioma were significantly higher than that in benign cystoparaglioma. Conclusion:The negative rate of SDHB immunohistochemistry in the tissues of malignant cystoganglioma was 66.7%. In the tissues of cystoganglioma with negative SDHB expression,EPAS1 was overexpressed,and the positive expression intensity of EPAS1 was positively correlated with the high expression of CgA and Ki-67. SDHB,EPAS1 and Ki-67 are the biological indicators for the prediction of malignant cystoparaglioma.