Abstract: Objective To analyze the clinical features,neuroimaging presentations,and treatment and prognosis of supratentorial primitive neuroectodemal tumors.Methods The clinical data of 6 patients with supratentorial primitive neuroectodemal tumors which were confirmed by histological examination and immunohistochemistry were retrospectively reviewed.Preoperative radiographies included CT and /or MRI in all patients,all patients underwent direct surgery, and received a course of postoperative radio-therapy,and / or chem-therapy.Intro-operative neuronavigation or intraoperative ultrasound was used in four patients.All patients were followed up from 6 to 24 months.Results The age of patients with SPNET is from 4 to 33 years old with mean age of 16.8.The incidence was about 0.6% of same period intracranial brain tumors in our hospital.The initial characteristic symptoms and signs of these patients included vomiting and headache,followed by motor weakness.MRI or CT features were low signal on T1-weighted images;strong contrast enhancement,low or similar signal on T2 weighted image.little perifocal edema on T2-weighted images could be found.The tumors of 6 patients were totally or sub-totally removed.During the operations the tumor often had rather distinct margin.There were no operative mortality and serious complications in this series.In the follow-up 3 patients were dead,survival time is 7,18 and 20 months respectively,3 were alive for 16,12,6 months.Conclusion The supratentorial primitive neuroectodemal tumors generally occurring in children was very rare,the chief complaint was always increased cranial pressure.The image features of supratentorial PNETs are typically bulky hemisphere masses which appear sharply circumscribed.Focus is always with intense contrast enhancement,but only mild perifocal edema,total removal is major treatment,radiotherapy and chemotherapy following can improve the patient's prognosis.

Key words: supratentorial primitive neuroectodemal tumors, operation, radiotherapy, chemical therapy