Inverted Papilloma, sphenoid sinus

36-year-old male with history of chronic nasal obstruction. There is an ovoid, solid appearing mass with STIR and FLAIR mildly hyperintense signal. On the STIR-weighted image, there is a slight cerebriform appearance of the lateral margin of the right sphenoid mass. The lesion enlarges the right sphenoid sinus, and there is mild diffusion restriction. The lesion enhances, and there is a tubular configuration of enhancing soft tissue arising from the right sphenoethmoidal recess. The findings are most compatible with an inverted papilloma of the right sphenoid sinus. Males are much more commonly affected than females by a ratio of 3-5:1. The lesions arise from the lateral wall of the nasal cavity, most frequently related to middle turbinate and maxillary ostium. Underlying squamous cell carcinoma transformation cannot be excluded.