2025 Volume 62 Issue 1 Pages 80-83
A healthy 9-year-old girl complained of pain in the right buttock and lower extremity, which led us to detect an intradural extramedullary tumor in the lumbar spinal canal. The patient underwent tumor resection. The tumor was grossly resected and histologically diagnosed as a mesenchymal chondrosarcoma (MCS). NCOA2 breaks detected by fluorescence in situ hybridization supported this diagnosis. The patient received alternate doses of vincristine, doxorubicin, cyclophosphamide, ifosfamide, etoposide, and local proton irradiation for a total dose of 50.4 Gy. She was recurrence-free at one year and two months after diagnosis. Intradural extramedullary MCS is extremely rare, with 60% of the previously reported cases occurring in children. Diagnosis is primarily based on histology. However, a disease-specific fusion gene, HEY1::NCOA2, has been identified and is useful for diagnosis. The clinical characteristics of intraspinal MCS may differ from those of common MCS, and further accumulation of cases is required.
