Abstract: Objective To investigate the clinical features of peripheral primitive neuroectodermal tumor （pPNET） for better treatment and prognosis. Methods The medical records of 80 pPNET patients in Jinling Hospital from March 2001 to July 2015 were reviewed， including the clinical features， diagnosis， treatment and survival analysis after follow-up visits.
ResultsThere were 44 males and 36 females with the median age of 22.0 years. The primary tumor lesion could be bone or soft tissue with 8 cases of head and neck， 40 cases of limbs， 2 cases of vertebral bodies， 7 cases of vertebral canal， 2 cases of clavicle， 5 cases of chest wall， 4 cases of lung， 3 cases of mediastinum， 8 cases of abdominal and pelvic cavity and 1 case of perianal， appearing as a gradual increase in mass and accompanying ache and function restriction. Diagnosis depended mostly on pathology， especially immunohistochemical analysis， where CD99， FLI-1， Syn， Vimentin and S-100 were often positively expressed. There were no specific indexes on laboratory or imageology examinations. Complete excision， if possible， was the first treatment option， preferably in combination with chemo-and／or radio-therapy. The medium overall survival was 26.9 months with 1-， 2-， 3-and 5-year survival rates of 85.2%， 54.3%， 42.6% and 28.5%. Moreover， it was indicated by Cox regression analysis that patients with tumors greater than 10 cm in major axis and patients who received no complete excisions often had poor prognosis. Conclusion pPNET is an extremely malignant tumor that often happens to adolescents. Accurate diagnosis mostly depends on pathology. Surgery combined with chemo-and／or radio-therapy in time could prolong the survival time.