A 17 yr old girl presents with ovarian tumor. USG shows predominantly solid components. Tumor markers CA-125 and AFP are negative, however LDH is raised. Which one of the following can be the most likely tumor?

Placental alkaline phosphatase (PLAP) and lactate dehydrogenase (LDH) are produced by up to 95% of dysgerminomas, and serial measurements of LDH may be useful for monitoring the disease. Dysgerminomas are the most common germ cell tumours Germinomas are found in both sexes and may arise in gonadal or extragonadal sites. The latter include the midline structures from the pineal gland to the mediastinum and the retroperitoneum. The capsule is slightly bosselated, and the consistency of the cut surface is fleshy and pale tan to gray-brown in color. The large round, ovoid, or polygonal cells have abundant, clear, very-pale-staining cytoplasm, large and irregular nuclei, and prominent nucleoli. Dysgerminomas are very sensitive to radiation therapy & is the only radiosensitive ovarian tumor.and doses of 2,500 to 3,500 cGy may be curative, even for gross metastatic disease.