摘要目的：探讨P504s在胰腺实性假乳头瘤（SPTP）和胰腺神经内分泌肿瘤（PanNET）鉴别诊断中的作用。方法收集2007年至2014年确诊的43例SPTP、41例PanNET病例，采用免疫组织化学EnVision方法观察波形蛋白、CD10、嗜铬粒素A、突触素、β-catenin、CD99、P504s等多项免疫组织化学抗体在两组肿瘤中的表达情况，重点阐述P504s的鉴别诊断中的作用。结果波形蛋白、CD10、嗜铬粒素A、突触素、CD99等免疫标志物在这两组织肿瘤中都有不同程度的表达，P504s在所有SPTP中呈胞质颗粒状阳性表达，所有PanNET肿瘤均不表达P504s。结论 P504s对SPTP的诊断具有敏感性，是鉴别SPTP和PanNET一个有价值的免疫标记指标。

abstractsObjective To study the significance of P504s in differential diagnosis between solid pseudopapillary tumor of the pancreas(SPTP) and pancreatic neuroendocrine tumors(PanNET).Methods Forty-three patients with SPTP and 41 patients with PanNET encountered during the period from 2007 to 2014 were recruited.Immunohistochemical study for vimentin, CD10, chromogranin A, synaptophysin, beta-catenin, CD99 and P504s in SPTP and PanNET was performed.The diagnostic value of P504s in differentiating SPTP from PanNET was analyzed. Results Immunohistochemical study showed that vimentin, CD10, chromogranin A, synaptophysin and CD99 were expressed both in SPTP and PanNET.All cases of SPTP showed granular cytoplasmic expression of P504s, whereas those of PanNET were negative. Conclusion P504s is a sensitive and useful marker for SPTP and can be used in the distinction between SPTP and PanNET.