中文摘要：

目的分析小儿卵黄囊瘤的临床特点，探讨脂肪酸合酶（Fatty acid synthase，FASN）在小儿卵黄囊瘤中的表达及意义。方法回顾性分析26例卵黄囊瘤患儿临床资料，运用免疫组化检测26例卵黄囊瘤、17例未成熟畸胎瘤、1例胚胎性癌及12例相关部位正常组织标本中FASN的表达情况。结果26例小儿卵黄囊瘤发病平均年龄2岁5个月，16例单纯以肿块就诊，5例单纯以局部继发症状就诊，5例同时具有肿块及局部症状。FASN在卵黄囊瘤的表达程度（73％）显著高于未成熟畸胎瘤（28％）、胚胎性癌（0％）、正常组织（16％）。FASN在性腺内和性腺外小儿卵黄囊瘤的阳性表达率分别为56％和100％。伴淋巴结或远处转移组和无转移组阳性表达率分别为100％和61％。FASN的阳性表达率与临床分期呈正相关。以上差别均有统计学意义。化疗前后FASN表达率分别为72％和75％，差别无统计学意义。结论小儿卵黄囊瘤起病隐匿，进展迅速，手术治疗联合化疗有效，FASN的表达可为诊治提供参考。

英文摘要：

Objetive To analyse the clinical characteristics and the expression and significance of FASN in infant yolk sac tumor. Methods 26 clinical datas of pediatric yolk sac tumors were analyzed. These 26 yolk sac tumors and another 17 immature teratomas, 1 embryonal carcinoma, 12 associated normal tissues were studied with immunohistochemical detection. Results The average age of these yolk sac tumors was 2 years and 5 months old. The chief complaint of 16 cases was mass. Meanwhile 5 cases were simply of local symptoms and 5 cases showed both mass and local symptoms. Positive expression rate of FASN was 73% in yolk sac tumors,28% in immature teratomas, none in embryonal carcinoma and 16% in normal tissues. Expression of FASN was higher in extragonadal yolk sac tumor in children（ 100% ） than in gonadal ones（56% ）. Positive expression rate was 100% in the group of lymphaden or distant metastasis, while 61% in the group of no metastasis. The expression rate of FASN in yolk sac tumor were positively correlated with clinical stages . There was no significant difference between yolk sac tumors without chemotherapy and ones with chemotherapy. Conclusions Yolk sac tumor has an early onset and is concealed,which is treated with surgery combined with chemotherapy. The expression of FASN may provide a reference for the diagnosis and treatment of infant yolk sac tumor.