Left ovarian teratoma means that the left ovary has a germ cell tumor. Ovarian teratomas are ovarian germ cell tumors, including immature teratomas and mature teratomas; teratomas are a group of tumors derived from primitive germ cells and are composed of polymorphous tissue, with the majority of the tumors being mature and cystic, while a few are immature and solid. Mature teratomas, also known as dermoid cysts, are benign ovarian tumors. Most of the tumors are cystic and unicompartmental, and the cavity is filled with oil and hair, or teeth and bone. Immature teratomas are malignant tumors, mostly solid with cystic areas, often with 2 to 3 embryonic layers and varying degrees of differentiation consisting of immature embryonic tissue, mainly primitive neural tissue. The clinical manifestations of left ovarian teratoma have no obvious symptoms in the early stage, and most of them are found by ultrasonography after physical examination or medical consultation after abnormal menstruation and small abdominal pain. If the left ovarian teratoma is a mature teratoma, it can be treated by surgical excision of the tumor, and if it is a postmenopausal woman, it can be treated by adnexectomy; if the left ovarian teratoma is an immature teratoma, it needs to be treated by a combination of surgery and chemotherapy. If you find a teratoma on the left side of the ovary, you need to go to the hospital in time to avoid delaying your condition.