Ewing sarcoma is a rare tumor in those older than 25 years of age (95% affected are between 4 and 25 years of age), and also uncommonly involves the axial skeleton (~15% involve axis). In this case, the patient is both unusually old and affected in an uncommon location. 

Approximately 40% of Ewing tumors show some amount of sclerosis, but sclerosis is more common in affected flat bones than in long bones, and is a feature in this case. 

The differential diagnosis in this case includes: metastatic lesion (breast, gynecologic, etc), lymphoma, myeloma, chordoma, osteosarcoma, and other unlikely primary bone tumors.