Objective:The authors report an extremely unusual presentation and management of a children pineal mixed germ cell tumor mainly composed of immature teratoma,aiming to summarize main theraptic points by literature review.Methods:A cystic lesion located in the rear of third ventricle in a child was detected3 years ago with no other therapy performed except for a ventriculo-peritoneal shunt.During the following 3 years,intermitted regular brain MRI demonstrated no evidence of lesion aggrandizement.However from 20 days before admission to our institute the patient began to present acutely with exacerbating clinical symptoms meanwhile brain MRI showed signs of abrupt revulsions of initial lesion without any incentive cause.Neurological examination revealed a significant rising of serum tumor marker level.Then surgical resection was performed immediately after admission which was followed by correlative two-course chemotherapy.Results:Postoperative brain MRI demonstrated totally removing of the lesion in rear of third ventricle.Serum tumor marker level decreased remarkably after surgery and declined to normal level after two-course chemotherapy.No obvious neurological deficit occurred except for short-term memory difficulty which gradually recovered within two weeks.Soon after the second course chemotherapy the patient was currently asymptomatic and returned to school.Conclusions:(1)To ensure definitive diagnosis and proper therapecutic protocols benefit from grasping clinical features of mixed germ cell tumor.(2)Overall preoperative investigation including serum tumor marker level is as critical as neurological imaging examination.(3)Surgical excision is confirmed to be the key modality of treatment.With the regarding of mixed germ cell tumor,never highlight total resection too much.(4)Postoperative adjuvant chemotherapy is recommended as further intensive treatment to improve the prognosis of mix germ cell tumor. Objective: The authors report an extremely unusual presentation and management of a children pineal mixed germ cell tumor mainly composed of immature teratoma, aiming to summarize main theraptic points by literature review. Methods: A cystic lesion located in the rear of third ventricle in a child was detected3 years ago with no other therapy performed except for a ventriculo-peritoneal shunt.During the following 3 years, intermitted regular brain MRI demonstrated no evidence of lesion aggrandizement. However from 20 days before admission to our institute the patient began to present acutely with exacerbating clinical symptoms meanwhile brain MRI showed signs of abrupt revulsions of initial lesion without any incentive cause. Neurological examination revealed a significant rising of serum tumor marker level. Clinical surgical resection was performed immediately after admission which was followed by correlative two-course chemotherapy. Results : Postoperative brain MRI demonstrated totally removing of the lesion in the rear of third ventricle. Serum tumor marker level decreased remarkably after surgery and declined to normal level after two-course chemotherapy. No apparent neurological deficit occurred for short-term memory difficulty which eventually recovered within two weeks. course chemotherapy the patient was currently asymptomatic and returned to school. Conclusions: (1) To ensure definitive diagnosis and proper therapecutic protocols benefit from grasping clinical features of mixed germ cell tumor. (2) Overall preoperative investigation including serum tumor marker level is as critical (3) Surgical excision is confirmed to be the key modality of treatment. Writh the regarding of mixed germ cell tumor, never highlight total resection too much. (4) Postoperative adjuvant chemotherapy is recommended as further intensive treatment to improve the prognosis of mix germ cell tumor.