Whether an ovarian teratoma 15 x 10 mm is serious or not needs to be determined based on the benign or malignant nature of the teratoma. Ovarian teratoma is a kind of female germ cell tumor, the vast majority of them are benign tumors, but there are a small number of malignant transformation or immature teratoma, which are malignant tumors. Regardless of the size of the malignant teratoma, there is a risk of infiltration and metastasis to the surrounding tissues, so if the ovarian teratoma is malignant, it will be more serious. If the size of the ovarian teratoma is only 15 x 10 millimeters, and it is a mature teratoma, then this situation is not serious, and can be regularly reviewed or laparoscopic surgery to be removed. If you have an ovarian teratoma, it is important to treat it accordingly under the guidance of your doctor.