The patient went on to have surgery. 

Histology

Gross description: The specimen showed a lobulated poorly demarcated blue-tinged intramedullary lesion that measures 3.5 x 2.8 x 2.5 cm. The lesion is completely confined within the medullary cavity with areas of endosteal scalloping but there is no breakthrough the cortical bone as well as no soft tissue extension. Negative for dedifferentiation

Final diagnosis:  chondrosarcoma (intermediate grade, grade 2/3)