There are benign and malignant teratomas, mature teratomas are benign tumors while immature teratomas are malignant tumors, and the benign or malignant nature of the tumor depends mainly on the degree of differentiation of the tissue. Benign teratomas, i.e. mature teratomas, also known as dermoid cysts, are composed of well-differentiated tissues of ectodermal, mesodermal, and endodermal origin, and are more often unilateral, with a few being bilateral. Most of them are cystic, often with nodular projections, and the cystic cavity may contain sebum, hair, teeth, etc. The malignancy rate of mature teratomas is 2%-4%. If the size of the tumor is relatively small, there is usually no special discomfort symptoms, gynecological examination can be found by chance. When the teratoma is large in size, the patient may feel abdominal distension, or touch a lump in the abdomen. Teratoma pressure on the bladder, there will be frequent urination, urinary symptoms. Benign teratoma should be detected early, early treatment, once diagnosed, must be operated as soon as possible to avoid malignant lesions. The prognosis after surgery is relatively good, usually no recurrence, but if the tumor is not completely or cleanly removed, there is also a possibility of recurrence.