The patient went on to have a complex resection of L4 vertebral body including left side posterior elements and associated soft tissues, adjacent intervertebral discs, the inferior body of L3 and superior body of L5. 

Histology

Microscopic Description:

Sections show a clear cell neoplasm arranged as sheets and as lacunae within a cartilaginous matrix. Some woven bone is produced, osteoclasts are present and the lesion is more vascular than a conventional chondrosarcoma. Cells have abundant clear and faintly eosinophilic cytoplasm which is PAS positive in a strong, granular pattern. Nuclei are centrally-located and show low-grade atypia, with occasional mitoses identified. Immunostains demonstrate the lesional cells to be intensely positive for S100, but negative for keratins, EMA, synaptophysin and chromogranin.

Final diagnosis: 

Clear cell chondrosarcoma (low-grade, grade 1/3)