A 46-year-old woman presented with cough for over 20 days, unrelieved by anti-inflammation treatment. Diffuse wall thickening and mildly luminal stenosis of the lower trachea and both main bronchi were observed on chest CT examination. The pathology after bronchoscopy confirmed non-Hodgkin lymphoma (mucosa-associated lymphatic tissue, MALT). FDG PET/CT was performed to evaluate the extent of the disease, which demonstrated the abnormal FDG accumulation in the diffusely thicken wall of trachea and bronchi, without lymph nodes and other extranodal tissue involvement.