A Case of Primary CNS Embryonal Rhabdomyosarcoma with PAX3-NCOA2 Fusion and Systematic Meta-Review

Purpose: Primary central nervous system (CNS) rhabdomyosarcomais a rare mesenchymal tumor predominantly seen in children and associated with a poor outcome. We report a case of primary CNS rhabdomyosarcoma with PAX3-NCOA2 fusion and presenta systematic meta-review of primary CNS rhabdomyosarcoma to characterize this rare tumor.Methods: We present the case of a 6-year-old boy with primary CNS rhabdomyosarcoma in the posterior fossa. In a systematic meta-review, we compare the demographic data of primary CNS rhabdomyosarcoma with data of rhabdomyosarcoma at all sites from the SEER database and analyze clinical factors associated with survival outcome.Results: Our patient underwent gross total resectionand receivedvincristine, actinomycin-D, cyclophosphamide with early introduction of concurrent focal radiation and remained alive with no evidence of disease for 2 years after the end of therapy. Histopathological review revealed embryonal-type rhabdomyosarcoma, and whole-transcriptome analysis revealed PAX3 (EX6)-NCOA2 (EX12) fusion. In all, 77 cases of primary CNS rhabdomyosarcoma were identified through the meta-review. The demographic data of primary CNS rhabdomyosarcoma were similar to dataof rhabdomyosarcoma at all sites. Overall and event-free survival outcomes were available for 64 and 56 patients, respectively, with a 3-year OS of 29.5%and a 3-year EFS of 26.2%. The group that received trimodal treatment exhibited better survival outcomes, with a 3-year OS of 57.4%and a 3-year EFS of 46.3%.Conclusions: Primary CNS rhabdomyosarcoma shares common histological, molecular, and demographic features with non-CNS rhabdomyosarcoma. A trimodal treatment approach with early introduction of radiation therapy may result in favorable survival outcomes.