SYP and neoplasm: Immunohistochemical examination of the tumor was as follows: cytokeratin- (Figure 3A1, 3A2), epithelial membrane antigen (EMA)- (Figure 3B1, 3B2), vimentin+ (Figure 3C1, 3C2), S-100 sported+ (Figure 3D1, 3D2), synaptophysin+ (Figure 4A1, 4A2), chromograninA+ (Figure 4B1, 4B2),The Ki-67 labeling index was less than 1%.(Figure 4C1, 4C2),These findings led to a histological diagnosis of non-chromaffin paraganglioma of the retroperitoneum.