Peripheral primitive neuroectodermal tumors in 18 cases

Abstract

Objective To discuss the clinical and pathological features,diagnostic standards,therapy and prognosis of peripheral primitive neuroectodermal tumors(pPNET)so as to improve diagnostic and therapeutic levels.Methods Clinical data of 18 cases of pPNET were analyzed retrospectively.Histopathologically,tumors were characterized by uniform small round or oval cells and nest-like or dense sheets structures surrounded by spare fibrovascular stroma.The HomerWright rosettes were observed in some cases,Immunohistochemically,the tumor cells showed higher positive rates for CD99,Syn,NSE and Vim.Results Six patients received surgical alone and twelve patients received chemotherapy and/or radiotherapy after surgery.The median survival time for two groups was 17 months and 22 months,respectively.The difference was significant (P＜0.01).The overall survival time was 7-36 months and the median survival time was 20 months.1-year survival rate was 89%,2-year survival rate was 39%.Both the ways of treating and metastasis in preliminary diagnosis were important factors affecting the prognosis.Conclusions PNET mainly attacks teengers and has poor prognosis.The clinical pathological features and immunohistochemical expression can help to diagnose the disease.Surgery combined with chemotherapy and/or radiotherapy was the best choice. Key words: Peripheral primitive neuroectodermal tumors ; Diagnosis; Therapy; Prognosis