A Rare Thoracolumbar Spinal Atypical Teratoid/Rhabdoid Tumor in a 7-Year-Old Child: Diagnostic Challenges and Therapeutic Considerations.

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare, highly aggressive embryonal neoplasm of the central nervous system, primarily diagnosed in children under three years of age, with spinal presentations accounting for fewer than 2% of patients. This report describes an unusual primary thoracolumbar spinal AT/RT in a 7-year-old girl who presented with severe, rapidly progressive pain impairing mobility. Magnetic resonance imaging revealed a large intradural extramedullary mass extending from T11 to L3 with marked compression of the conus medullaris and cauda equina. Surgical resection was performed, and histopathological evaluation confirmed rhabdoid morphology with characteristic immunophenotypic features, including loss of nuclear SMARCB1 (INI1) expression and elevated proliferative index, consistent with AT/RT. This case report highlights the diagnostic complexity due to overlapping features with other pediatric spinal tumors, necessitating comprehensive histological, immunohistochemical, and molecular analyses for accurate classification. Discussion integrates the patient tumor profile within the framework of WHO 2021 molecular subgroups, underscoring the clinical heterogeneity and poor prognosis associated with spinal AT/RT, particularly the aggressive AT/RT-MYC subtype. Despite maximal surgical and multimodal therapy, outcomes remain dismal, emphasizing the urgent need for collaborative research exploring targeted molecular and immunotherapeutic strategies. This case report expands limited literature, offering valuable insights for early recognition and management of spinal AT/RT in older pediatric patients.