Atypical Teratoid/Rhabdoid Tumor of the Conus Medullaris

Introduction: Atypical teratoid/rhabdoid tumor (AT/RT) is a rare tumor of the central nervous system, especially when involving the spinal column or spinal cord. Case Presentation: We present a case of a 5-year-old girl with progressive bilateral lower extremity pain found to have a discrete nodular lesion of the conus with mild heterogeneous enhancement. Surgical decompression and resection demonstrated a pathologic tumor consistent with AT/RT with loss of INI1 protein on immunohistochemistry. Discussion and Conclusion: AT/RT lesions of the conus medullaris are exceedingly rare and associated with extensive disease. We report a rare case of AT/RT with selective involvement of the conus medullaris, as well as describe the surgical, radiographic, and pathologic findings of this tumor.