The appearance of the lesion described above is consistent with an liposclerosing myxofibrous tumor (LSMFT) , although could also represent fibrous dysplasia. 

In either case, this is most likely a benign lesion with no need for treatment, just occasional imaging follow up, as 10-16% of LSMFT lesions reportedly undergo malignant degeneration, although that estimate seems high based on this authors experience.