Fig. 2

Seventy-seven-year-old woman with squamous cell papilloma of the trachea. a Axial and b coronal CT imaging demonstrating frond-like polypoid masses extending into the tracheal lumen. c 3D VR image shows the large extent of the lesion and the significant airway narrowing. d Pathology reveals papillary squamous cell proliferation with fibrovascular core and bland morphology