<s>[INST] context: Germinomas (pure germ cell tumors), which are tumors that respond well to treatment. Germinomas usually can be cured using chemotherapy and/or radiation therapy. Ninety percent of germ cell tumors are gonadal, which means they begin in the reproductive cells of the testes (testicular tumors) or ovaries (ovarian tumors). Germ cell tumors that appear in other pas of the body - including the abdomen, chest, neck, head and brain (the areas where the cells migrate within a developing embryo) - are called extragonadal germ cell tumors. The most common types of malignant germ cell tumors are dysgerminomas >immature teratomas>endodermal sinus tumors. Dysgerminoma 30% to 40% of all ovarian cancers of germ cell origin occur in young women 20% to 30% of ovarian malignancies associated with pregnancy are dysgerminomas. Tumor markers: LDH, PLAP Immature Teratomas elements that resemble tissues derived from the embryo second most common germ cell malignancy and accounts for 10% to 20% of all ovarian malignancies seen in women younger than 20 years [/INST] question: A left side ovarian tumor with HCG 4 IU/L, Normal AFP, LDH raised. Which of the following is the most likely diagnosis | options: A: Choriocarcinoma B: Dysgerminoma C: Embryonal cell tumor D: Malignant Teratoma | answer: B </s>