Epid-26. Clinical and Histological Characterization of Primary Central Nervous System Sarcoma in Pediatrics. A Single Institution Experience in a Middle-Income Country

Abstract

INTRODUCTION Primary central nervous system (CNS) sarcomas are rare mesenchymal non-meningothelial tumors accounting for less than 0.2% of intracranial lesions. Diagnosis and management are challenging due to the current lack of substantive clinical, histological and molecular data. METHODS We retrospectively identified all patients with diagnosis of primary CNS sarcoma at the Hospital Fundación Pediatrico la Misericordia (HOMI) in Bogota, Colombia. We collected patient demographics, disease characteristics, and outcomes for analysis. RESULTS Between 2008 and 2020, twenty-four consecutive patients were diagnosed at the HOMI representing 6% of all CNS tumors diagnosed over the same time period. The median age at presentation was 9.48 years (range:1.6–13.4). The median time of symptoms prior to diagnosis was 2 weeks (0.1–24). The most common presentation was headache (21/24- 89%) and vomiting (19/24- 79%). The frontal lobe was involved in 63% of patients (15/24) and only one patient presented with a cerebellar lesion. Histologically, these tumors were characterized by a pleomorphic spindle cell architecture and high mitotic activity. All samples lacked immunoreactivity to GFAP, CD34, EMA, and S100 and all samples had strong nuclear immunopositivity for TLE-1; BCL-2 was reactive in eighteen cases. Gross total resection was attained in fifteen patients, most patients received focal radiation therapy and ICE chemotherapy. Progression-free survival at 12 and 24 months was 57% and 31% respectively. Overall survival was 77% at 12 months and 39% at 24 months. Thirteen patients relapsed, 11 presented with local failures, and 2 with intracranial recurrences outside of the radiation field. CONCLUSION Our study identifies TLE-1 as a diagnostic marker of primary CNS sarcoma, a highly malignant supratentorial tumor of childhood. Further molecular studies are urgently needed to elucidate the biology of this disease and the unusually high incidence observed in the Colombian pediatric population.