Fig. 12.

Inverted papilloma of the right sphenoid sinus in a 71-year-old male patient. MRI shows a solid expansive lesion in the right nasal fossa in correspondence to the spheno-ethmoidal recess (white arrows). That lesion has similar SI to the grey matter on axial T2W images (a and b) with focal “cerebroid” appearance (b, white curved arrow) and moderate enhancement on T1W fat-saturated CE image (c). Axial bone reconstruction algorithm CT reveals a focal plaque-like hyperostosis in the anterior wall of the right sphenoid sinus (d, white dotted arrow), as the likely site of tumour origin