| Objective:Peripheral primitive neuroectodermal tumors(pPNET)are rare and highly malignant small round cell tumors.At present,most reports about pPNET are single case reports and researches based on small sample sizes.There is still a lack of knowledge about clinical features,biological behavior,and prognostic factor of this disease.The purpose of this study is to illustrate the clinical manifestations,diagnosis,treatment,and to discuss the prognostic factors of pPNET,providing more data to the understanding of this rare disease.Methods:The clinical data of 56 pathologically confirmed pPNET patients who were treated in the Affiliated Cancer Hospital of Zhengzhou University from March 2003 to December 2019 were retrospectively analyzed.Hematoxylin-eosin(HE)staining and immunohistochemical staining were performed using samples collected from surgical operations and biopsies.Kaplan-Meier method was performed to identify whether gender,age,original anatomical location,size,lymphatic metastasis,distant metastasis,stage,surgical operation,surgical complications,neoadjuvant chemotherapy,cycles of adjuvant chemotherapy,surgery after recurrence,and results of immunohistochemical staining are potential prognostic factors of pPNET.Factors with significant p values in the Log-rank tests were subsequently subjected to multivariate analysis using Cox regression analysis.Results:A total of 27 males and 29 females were included in this study,and the ratio of male to female was 0.93:1,with a median age of 21.5 years(9 months-63 years).The positive rate of CD99,NSE,Syn,Vimentin,CD56,and S-100 was 100%,34%,46%,73%,55%,and 20% respectively.Ki-67 protein expression ranges from 2% to 90%,with a mean expression of 45%.Fluorescence in situ hybridization(FISH)analysis was performed in 9 cases and the results showed that gene split happened in all 9cases.In total,47 patients received surgical operation and 28 patients relapsed,with12 patients receiving second excision.The mean and median overall survival(OS)were 23.18 and 15.50 months.The mean and median progression-free survival(PFS)were 13.49 and 9.00 months.The 1-,3-,and 5-year PFS rates were 37.50%,10.71%,and 1.78% respectively.The 1-,3-,and 5-year OS rates were 76.79%,14.29%,and5.36% respectively.The univariate analysis suggested that original anatomical location,tumor size,lymphatic metastasis,distant metastasis,stage,surgical operation,cycles of adjuvant chemotherapy,surgery after recurrence were prognostic factors for OS.Gender,original anatomical location,lymphatic metastasis,distant metastasis,stage,surgical operation,cycles of adjuvant chemotherapy were prognostic factors for PFS.The Cox regression analysis suggested that original anatomical location,tumor size,and surgical operation are prognostic factors for OS.Surgical operation is a prognostic factor for PFS.Conclusion:pPNET are and highly malignant small round cell tumors that mostly happen in children and teenagers.The clinical manifestations and radiological features are not specific.Original anatomical location,tumor size,and surgical operation are prognostic factors for OS.Surgical operation is a prognostic factor for PFS.Total resection of tumor tissue and early diagnosis can improve survival. |
