儿童卵黄囊瘤病理学特征及鉴别诊断

Pathological characteristics and differential diagnosis of yolk sac tumor in children

目的了解儿童卵黄囊瘤(YST)的组织形态学特征,明确免疫组织化学特点及其在YST病理学诊断中的作用,探讨YST鉴别诊断要点。方法回顾总结21例YST(性腺8例,非性腺13例)的组织形态学及免疫组织化学特征。结果 YST的组织形态学表现多样,具有微囊和网状结构17例,内胚窦结构16例,腺管—腺泡结构10例,乳头状结构8例,巨囊结构和肠型结构各3例,多囊泡卵黄囊样结构2例,黏液瘤样结构1例。免疫组织化学染色甲胎蛋白(AFP)阳性表达20例(95.24%),细胞角蛋白(CK)阳性表达21例(100%),波形蛋白(Vim)阳性表达16例(76.19%)。结论儿童YST可发生于性腺(睾丸和卵巢),亦可发生于非性腺部位(骶尾部、盆腹腔、小脑和软组织等)。YST组织形态表现具多样性,常见特征性结构有微囊和网状结构、内胚窦结构、腺管—腺泡结构和乳头状结构,巨囊结构、肠型结构、黏液瘤样结构和多囊泡卵黄囊样结构等较少见。组织形态学及免疫组织化学特征有助于明确YST的病理学诊断和鉴别诊断。

Objective To investigate the pathological features of yolk sac tumor（YST） in children, determine the immunohistochemical characteristics and their role in pathological diagnosis of YST, and discuss the differential diagnosis of YST. Methods The clinical data of 21 cases of YST were retrospectively summarized, among which 8 were concerned with gonad, and the other 13 nongonad. The characteristics of histology and immunohistochemical staining were observed. Results There were various pathological organizations for YST. There was micro capsule and reticular structure in 17 cases, embryo sinus structure in 16 cases, gland tube-gland bubble structure in 10 cases, papillary structure in 8 cases, giant cystic structure in 3 cases, intestinal type structure in 3 cases, polycystic bubble yolk sac sample structure in 2 cases and mucus tumor sample structure in 1 case. Immunohistochemical staining revealed that the positive expression rate of alphafetoprotein （AFP） was 95.24% （20/21）, that of cytokeratin （CK） was 100% （21/21）, and that of vimentin （Vim） was 76.19% （16/21）. Conclusion Besides gonad （testis and ovary）, YST in children can also involve non-gonad parts such as sacroiliac region, abdominopelvic cavity, cerebellum and soft tissues. The histological features of YST are diverse, which are characterized by the common structures such as micro capsule and reticular structure, inner embryo sinus structure, gland tube-gland bubble structure and papillary structure and rare structures such as giant cystic structure, intestinal type structure, mucus tumor sample structure and polycystic bubble yolk sac sample structure. Histomorphological characteristics and immunohistochemical findings may help to determine the pathological diagnosis and differential diagnosis of YST.