[Yolk sac tumors of the ovary]

Dysgerminoma, teratoma and chorion carcinoma originating of germ cells, are well known tumours of the ovary. Tumours arising from the yolk-sac formerly called embryonal carcinoma- are seldom observed, their morphological feature is not well known. Author reports four cases of yolk-sac tumour, discusses their morphology, histogenesis and prognose.