胸部原始神经外胚层瘤5例临床病理分析

目的 探讨胸部原始神经外胚层瘤(PNET)的临床病理特征、免疫学表型及其鉴别诊断。方法 对5例发生于胸部的PNET进行光镜观察和免疫组化研究。结果 5例PNET中4例为女性，1例男性，年龄12～52岁，平均27．0岁。肿瘤体积较大，平均直径11．4cm，无包膜或包膜不完整。镜下：肿瘤由小圆细胞构成，细胞胞质少，部分区域肿瘤细胞胞质透亮，可见Homer-Wwright菊形团和假菊形团。免疫表型：5例CD99(MIC2)、NSE阳性，4例synaptophysin阳性，3例vimentin阳性，2例S-100蛋白阳性。结论 胸部PNET是较少见的高度恶性软组织肿瘤，其诊断主要依据病理形态学特征及免疫组化标记。

Thoracic primitive neuroectodermal tumor: a clinicopathologic study of 5 cases

Purpose To study the clinicopathologic and immunohistochemical characteristics of thoracic primitive neuroectodermal tumor (PNET) and its differential diagnosis. Methods Light microscopy and immunohistochemical stains were performed in 5 cases of thoracic PNET. Results There were 4 female and 1 male patients,aged from 12 to 52 (mean age 27.0). Those tumors were large in size (mean diameter 11.4 cm),with incomplete capsule or no capsule. Histologically,the tumors were composed of small round cells with little cytoplasm,and partly were transparent cells. There were Homer-Wright rosectes and pseudo-rosectes in tumors. Immunohistochemically,all cases expressed CD99 (MIC2) and NSE,4 cases expressed synaptophysin,3 cases expressed vimentin,2 cases expressed S-100. Conclusion Thoracic PNET is a rare highly malignant soft tumor,and its differential diagnosis must be established on characteristics of pathology and immunohistochemistry.