Recently, Dr. Xuewu Zhou, deputy chief of pediatric surgery of our hospital, successfully performed laparoscopic resection of a 7-year-old girl with a huge right ovarian teratoma, successfully removing a 15×12×2 cm teratoma, which also contained teeth, brain tissue and hair. Nana is 7 years old and is a very quiet little girl. The night before she was admitted to the hospital, her mother noticed that her belly was bulging when she was giving Nana a bath and felt bad. Due to the complexity of her condition, Nana was admitted to the pediatric surgery department for further examination and treatment. On August 5, with the cooperation of his assistant Dr. Xi Qi, Dr. Zhou Xuewu performed laparoscopic resection of a huge right ovarian teratoma on Nana, which was found to be on her right ovary. In order not to affect Nana’s future fertility, the mass was dissected and successfully removed while preserving her right ovary. Teeth, brain tissue, and hair were visible inside the removed mass. Postoperative pathology revealed that the mass was a benign cystic mature teratoma growing in the left ovary. It is understood that cystic mature teratoma is the most common benign ovarian tumor in pediatric patients, accounting for 65.6%71.1% of all ovarian cysts. The tumor originates from germ cells with allogenic differentiation and can occur at any age. The early symptoms of tumor are not obvious, but can be detected only after the tumor has protruded into the abdominal cavity when it is large, and can cause constipation, difficulty in defecation, urinary retention and other symptoms caused by occupancy. Deputy Chief Physician Zhou Xuewu reminded that in recent years, the incidence of childhood tumors is on the rise. In the early stage of tumor, if parents observe carefully, they can still find the abnormal condition of children early. In daily life, parents should be highly alert to some abnormal reactions and symptoms of children, such as unexplained mass, low fever; weight loss, no weight gain or loss; weakness, pale face; unstable gait and local lumps, etc., and go to hospital for consultation in time. In addition, routine pediatric physical examination is necessary for early detection and treatment of diseases.