Bone scan hot spots in a patient with lung cancer: ischaemic necrosis of bone mimicking metastatic carcinoma.

A 62-year-old man complained of a pain in his leg four months after radical surgery for a bronchial adenocarcinoma. Skeletal scintigraphy showed increased uptake of isotope in the lower femur and upper tibia corresponding to an abnormal area on the plain radiographs. Bone metastases were thought to be the most likely cause of these findings. Since the appearances were not entirely typical, bone biopsy was undertaken to confirm the diagnosis. This showed ischaemic necrosis of bone, related to a previous acute arterial occlusion. In view of the serious implications for a patient if an erroneous diagnosis of metastatic disease is made following potentially curative treatment for cancer, such a diagnosis should be proven, not assumed. Bone biopsy should be considered when solitary skeletal lesions develop in radically treated cancer patients with no other evidence of metastasis.