A sclerotic lesion on CT is indeterminate, possibly representing bone island versus blastic metastasis. If history of cancer such as breast cancer, nuclear medicine whole body bone scan and/or PET/CT can serve as a tiebreaker. Lack of hypermetabolic activity on your bone scan favors benign bone island (or treated bony metastasis).
I am not qualified to answer your question from a medical standpoint, but I would be a little apprehensive to not look into the CT scan results also. maybe get a second opinion? i know I would.