Spinal chondrosarcoma arising from a solitary lumbar osteochondroma

Chondrosarcoma is a primary malignant neoplasm of cartilage-forming cells that rarely involves the axial skeleton, typically affecting skeletally mature patients. It may arise as a primary bone tumour or as a secondary lesion from a pre-existing benign cartilaginous neoplasm such as an osteochondroma or enchondroma. We report the case of a 68-year-old female who presented with a mildly painful paraspinal mass lesion as a result of malignant degeneration of a previously unknown solitary lumbar osteochondroma into a large chondrosarcoma. The characteristic imaging findings on cross-sectional imaging techniques are reviewed and illustrated, along with an outline of relevant clinical and therapeutic aspects.