RESUMEN
Atypical teratoid rhabdoid tumors (ATRTs) are rare embryonal tumors comprising 1-2% of all pediatric CNS neoplasms. Spinal ATRTs are even more uncommon, accounting for 2% of all reported ATRT cases. Despite their rarity, ATRTs affect young children disproportionately and are characterized by a high malignant potential due to a heterogeneous cellular composition and inactivating mutations in the SMARCB1 (90%) and SMARCA4 (10%) genes. A 15-month-old female presented with a 2-week history of decreased lower extremity movement and new-onset need for assistance with ambulation. MRI lumbar spine revealed a contrast-enhancing intradural mass at the L3-L4 level with iso-intensity on T1 and T2 sequences. The patient subsequently underwent subtotal tumor resection (â¼80%) given concerns for maintaining neurological function. Final pathology was consistent with spinal ATRT, and she later underwent adjuvant chemoradiation therapy per ACNS0333 protocol. She has since remained in remission with age-appropriate developmental milestones over the past 2 years. ATRTs should be considered in the differential diagnosis of intradural spinal lesions, especially in the pediatric patient population. Clinical course, presentation, and diagnosis is often delayed due to the rarity of these tumors, but contrasted craniospinal MRI is key for diagnosis and histopathology with IHC staining showing loss of INI is confirmatory. While gross total resection is the goal, maximal safe tumor resection should be prioritized in order to preserve neurological function. Adjuvant chemoradiation following gross total/subtotal resection has been shown to significantly improve overall survival.
RESUMEN
BACKGROUND: Mesenchymal chondrosarcoma (MCS) is an aggressive subtype of chondrosarcoma that occurs extremely rarely in the central nervous system. Patients often present with pain or sensorimotor deficits, and resection is considered the gold standard. The role of adjuvant radiation and/or chemotherapy is largely unknown. OBSERVATIONS: A 22-year-old male presented with a 4-month history of progressive back and bilateral leg pain. He underwent imaging workup with magnetic resonance imaging of the lumbar spine and was found to have an intradural, extramedullary, heterogeneously enhancing mass spanning the L4-5 vertebral levels. Intraoperatively, a lobular, partially calcified mass with a ventral dural attachment displacing the nerve roots laterally was observed. The mass was removed en bloc, and the patient later underwent adjuvant radiotherapy, with no evidence of recurrence 2 years following surgery. LESSONS: Spinal MCS is extremely rare and often presents with a more aggressive course than conventional chondrosarcoma. Radiological diagnosis is challenging, as the tumor mimics different pathologies. The presence of calcifications, heterogeneous enhancement, and a more rapid clinical course as well as the presence of HEY1::NCOA2 gene fusion, which can be detected by surrogate immunohistochemistry, aids in diagnosis. Resection is the standard of care, and adjuvant radiation may be considered to reduce local recurrence, although further studies are warranted.