Extraskeletal intraspinal mesenchymal chondrosarcoma; 18F-FDG PET/CT finding.

Mesenchymal chondrosarcoma is a rare and aggressive form of chondrosarcoma. The extraskeletal intraspinal type is even rare among the mesenchymal chondrosarcoma cases. We presented a case of a 17-year-old boy pathologically diagnosed with intraspinal mesenchymal chondrosarcoma. MRI showed multiple intradural extramedullary masses with contrast enhancement, without the evidence of brain lesion. On F-FDG PET/CT, hypermetabolism was observed in the lesions matched with enhancement on spine MRI. The lesions were well differentiated from spinal cord. In the case of hypermetabolic lesion in intradural and extramedullary lesion of the spinal cord, mesenchymal chondrosarcoma should be considered for the differential diagnosis.