Fig. 10.

Right spheno-ethmoidal ossifying fibroma as an incidental finding in a 79-year-old female patient. Coronal CT image (a) shows a well-demarcated expansile lesion with central fibrous density areas (white arrow), surrounded by an ossified rim (white dotted arrow). MRI (b, c, and d) shows a lesion with intermediate central SI (fibrous areas, white arrows) and a peripheral rim of low SI (ossified area, white dotted arrows). The central fibrous areas have low SI on axial T1W image (b), mixed SI on axial T2W image (c), and inhomogeneous SI on sagittal T1W fat-saturated CE image (d). The peripheral ossified rim and internal septa appear hypointense in all MRI sequences