Clinical characteristics and treatment analysis of primary meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumors: A report of 12 cases

Objective To investigate the clinical characteristics, treatment methods and prognosis of primary meningeal Ewing sarcoma/peripheral primitive neuroectodermal tumors (ES/pPNETs). Methods The clinical data of 12 patients who had been surgically treated from February 2008 to December 2017 at Department of Neurosurgery, Tongji Hospital, Tongji Medical School, Huazhong University of Science and Technology and in whom immunohistochemical staining results had confirmed the diagnosis of primary meningeal ES/pPNETs were retrospectively analyzed. A fluorescence in situ hybridization (FISH) analysis was performed in 4 cases.Of the 12 patients, 7 were males and 5 were females. The age ranged from 1 to 43 years, and the median age was 14.5 years. The disease duration ranged from 2 days to 7 months (median disease duration: 2 months). Postoperative chemotherapy was performed in 9 cases. Postoperative radiotherapy was performed in 7 cases. Results All 12 cases were misdiagnosed by MRI. Immunohistochemistry experiments revealed that 12 cases were positive for CD99. A FISH analysis was performed in 4 cases, and EWS/FLI1 translocation was detected in 3 cases.Gross total resection (GTR) was performed in 6 cases and subtotal resection (STR) in 6. The follow-up period ranged from 2 months to 84 months (median follow-up period: 20 months). One case was lost to follow-up after 24 months. At the last follow-up, local recurrence occurred in 7 cases, and distant metastasis occurred in 3 cases. The number of deaths was 9 and that of survivors was 2. The median survival time (MST) of 11 patients was 20 months. Of the 12 patients, the number of survivors in 1-year and 2-year were 9 and 6, respectively. The number of survivors in 1-year and 2-year were 5 and 4, respectively, in patients with GTR, while they were 4 and 2, respectively, in patients with STR. Conclusions Primary meningeal ES/pPNETs mostly occur in children and adolescents, and the misdiagnosed rate seems high. Gross total resection combined with adjuvant radiotherapy and chemotherapy could improve the prognosis of patients. However, the postoperative recurrence rate is high. Key words: Ewing sarcomas; Primitive neuroectodermal tumors; Disease attributes; Treatment; Prognosis