Lung sequestration and Pott disease masquerading as primary lung cancer with bone metastases on FDG PET/CT.

The chest x-ray from a 37-year-old man with a history of back pain showed a mass in the left lower lung, which prompted an FDG PET/CT study to evaluate the nature of the mass and possible metastases. The images revealed peripherally increased FDG activity in the left lower lung mass. In addition, there was intense FDG activity in 2 adjacent thoracic vertebrae on PET images corresponding to the regions of bone destruction on the concurrent CT. Therefore, a possible diagnosis of lung carcinoma with bone metastases was suggested. However, subsequent tests demonstrated that the left lung mass was in fact a lung sequestration, whereas the spinal lesions were due to Pott disease (tuberculous spondylitis).