Teratomas are divided into mature teratomas and immature teratomas. Mature teratomas are usually benign tumors with the possibility of malignancy, the malignancy rate is not considered high, about 2% to 4%. Immature teratoma itself is a malignant tumor, there is no malignant transformation, and metastasis will occur. 1. mature teratoma: mature teratoma is usually benign lesions, can be divided into solid and cystic, the tumor can grow in the skin, hair follicles, fat, muscle, digestive tract, thyroid or brain tissue and other parts of the growth. There is a possibility of malignant transformation, but the rate of malignant transformation is not high, because mature teratoma will not metastasize, after active treatment, the prognosis is good, but there is a possibility of recurrence. 2. Immature teratoma: Immature teratoma is a malignant tumor itself and may be associated with lymph node or distant metastasis. After active treatment, the 5-year survival rate of patients with immature teratoma may reach about 70%~80%.