In the past, if a patient had a history of malignant surgery in his or her past medical history, most physicians would assume, rather cavalierly, that it was a metastatic tumor once a bone lesion or bone scan with radioactive concentration or PET-CT was found somewhere. Recent foreign literature has found that this clinical mindset may be in error. The correct conclusion is that it is not necessarily so. Although a previous history of malignancy and a positive PET-CT of a tumor or lesion on bone tissue is found to be highly suspicious of possible metastasis, the diagnosis still needs to be made on a matter of fact basis. Some lesions on bone tissue are originally a different disease. Some concentrations found on bone scans may not necessarily be metastases. Treatment still requires a clear pathological diagnosis before further treatment. Otherwise, it may lead to further malpractice or serious complications from wrong treatment. The easiest way is to do local imaging such as MR for further confirmation and pathological puncture or biopsy if necessary.