Grigor Kenneth M
The Department of Pathology, University of Edinburgh Teviot Place, Edinburgh, EH8 9AG U.K.
Int J Androl. 1981 Mar;4 Suppl s4:35-48. doi: 10.1111/j.1365-2605.1981.tb00649.x.
Extra embryonic elements in germ cell tumours resemble the trophectoderm or yolk sac endoderm which are the extra embryonic membranes of the developing embryo. True chorionic (trophoblastic) differentiation with syncytiotrophoblast and cytotrophoblast, perhaps with a villous pattern, is rare and is associated with a very poor prognosis and with hCG production. Isolated syncytiotrophoblastic cells also produce hCG but are prognostically less sinister. Yolk sac elements occur in two thirds of non seminomatous germ cell tumours, and affect all age groups. Pure forms of yolk sac tumour (YST) occur but are not common except in infants. They are often associated with AFP production but AFP is not a specific marker for YST. Yolk sac tumours have a similar prognosis to malignant teratoma undifferentiated (MTU: embrvonal carcinoma).
生殖细胞肿瘤中的胚外成分类似于滋养外胚层或卵黄囊内胚层，它们是发育中胚胎的胚外膜。具有合体滋养层细胞和细胞滋养层细胞的真正绒毛膜（滋养层）分化，可能呈绒毛状模式，较为罕见，且与预后极差及hCG产生有关。孤立的合体滋养层细胞也产生hCG，但预后方面威胁性较小。卵黄囊成分见于三分之二的非精原细胞性生殖细胞肿瘤，且影响所有年龄组。纯形式的卵黄囊瘤（YST）存在，但并不常见，婴儿除外。它们常与AFP产生有关，但AFP并非YST的特异性标志物。卵黄囊瘤的预后与未分化恶性畸胎瘤（MTU：胚胎癌）相似。
