The improved prognosis of cancer patients has led to an increased incidence of both bone metastases and (impending) pathological fractures. A solitary bone lesion seen on radiography should never be assumed to be a metastasis. Preoperative biopsy is necessary in patients with a known malignancy and a solitary lytic bone lesion as well as in patients in whom the primary tumor is unknown, in order to prevent an incorrect operation (also known as 'whoops surgery'). If the patient has an (impending) pathological fracture, normal bone healing is not to be expected, not even after stable fixation. Surgical fixation of an impending pathologic fracture is recommended when radiography indicates that a length of more than 3 cm of the cortex of a long bone has been destroyed. If surgical treatment is necessary, it should support the whole long bone in order to enable full weight bearing. When the diagnosis of a bone lesion is uncertain, referral to an experienced treatment centre is recommended.