Abstract： Objective To summarize and analyze the pathological characteristics of solid pseudopapillary tumor of pancreas (SPTs).Methods The clinical data of 51 cases of SPTs were retrospectively analyzed.The immunohistochemical localizations of different markers (HSE,SYN,CD_(56),CD_(10),Nestin,Vim,a1-ACT,EMA,AE1/AE3 and CK19) on 39 SPTs were studied.Results Pathological features included a combination of solid and cystic components with pseudopapillae formation and degenerative regions without glands.Among the 39 cases of SPTs,the expression rate of NSE was 97.4%,the expression rate of CD_(56),CD_(10) was 84.6%,the expression rate of Nestin and Vim was 64% and 87%,the expression rate of S100 was 79.5%,the expression rate of a1-ACT and a1-AT was 82.1% and 79.5%,while the expression rate of SYN was 12.8%;however there was low expression and weak positive reaction of EMA,AE1/AE3 and CK19.Conclusions The typical pathological characteristics of SPTs may result from gradual degenerative changes induced anoxemia in some SPT's areas.The heterogeneity of SPTs on different antibody markers showed that the SPTs may be originated from pancreatic embryonic stem cells,and result from immature differentiation of the pluripotential stem cells during pancreatic genesis.