Patient: Description (onset time, main symptoms, hospital visited, etc.): The child, male, 17 years old, felt chest tightness at the beginning of September 2010, so he had a puncture biopsy, PET-CT, etc. When the results came out, (the diagnosis was malignant teratoma of anterior mediastinum, liver and lung metastases, multiple bone metastases throughout the body, the size of the teratoma was 14*14cm, the metastases on the liver was 7cm*7cm). We were admitted to Shanghai Cancer Hospital from September 27 to October 15, from October 27 to November 15, from November 27 to December 15, from December 27 to January 15, from January 24 to February 15, from February 27 to the beginning of March, and were treated with BEP chemotherapy six times in April, May and June. He was evaluated before the third, fifth, seventh and ninth chemotherapy sessions, and his condition improved compared with that at the time of admission. The evaluation showed that there was no change of tumor before and after, liver and kidney function, electrocardiogram and isotope indexes were normal, and the child continued to go to school after returning home. Professor Zhou, a diagnostician from the Cancer Hospital, said he had never seen such a case before, and Professors Hu and Wang, medical oncologists, were at a loss as to how to continue the treatment. Beijing Chest Tumor Tuberculosis Hospital Thoracic Surgery Department Yan Dongjie: 1, liver and lung metastasis, bone metastasis is PETCT diagnosis? 2.If it is malignant teratoma, the volume is generally large and some of the boundaries are not clear. 3, it is recommended to review the whole body to understand the liver, bone lesion changes. If necessary, do liver aspiration to clarify whether metastasis. 4.Because it is less than one year. It cannot be said that the treatment is effective yet. 5.If the boundary of mediastinal lesion is clear and there is no surgical difficulty, local surgical excision is recommended.