
Endodermal Sinus Tumour is one of the histological varieties of germ cell tumours. EST have also been referred to as yolk sac carcinoma because, they derived from primitive yolk sac, In the first 2 decades of life, almost 70% of ovarian tumours are of germ cell origin and one third of them are malignant. yolk sac tumour is the third most common malignant germ cell tumour of the ovary, comprising 10 to 15% overall and reaching a higher proportion among children. The EST (Yolk sac tumour) primarily affects the adolescent girls of age group 16 to 18 years. The gross appearance of an EST is soft greyish-brown which is usually well encapsulated and solid. Areas of necrosis and haemorrhage and small cystic spacesare often seen. A rate case of endodermal sinus tumour (Yolk sac tumour) of adolescence is presented. A 16 year old postmenar girl presented with lump abdomen and 3 months amenorrhea. Serum alphafeto protein was elevated. A fertility preserving surgery was done followed by 3 months amenorrhea. Serum. Alphafeto protein level was reduced that refletcs the response to chemotherephy.