Occult cancer detected by positron emission tomography/computed tomography image fusion.

A 60-year-old male in a high-risk group for lung cancer, who also had positive sputum cytology, underwent examination by chest plain radiography, chest computed tomography (CT) and bronchofiberscopy. However, initially no abnormal findings were detected with these diagnostic modalities. Furthermore, thin-section spiral chest CT disclosed only a slight thickness of the right side of the tracheal wall, while consequent re-examination by bronchofiberscopy revealed only a light ulcerative lesion in the same area. However, the existence of a primary tumor was not confirmed using these modalities. Therefore, FDG-PET (positron emission tomography with fluorodeoxyglucose) was performed and demonstrated accumulation corresponding to the anterior mediastinum, although the exact location of the tumor was unclear by FDG-PET alone. Therefore, FDG-PET/CT image fusion was performed and resulted in the detection of a tracheal carcinoma on the outside of the right side of the tracheal wall. The patient then underwent tracheal sleeve resection including the tumor and tracheoplasty accompanied with wrapping using the flap of the thymus right lobe. To the best of our knowledge, this is the first reported case of tracheal carcinoma detected by FDG-PET/CT image fusion with consequent radical resection.