The T1-weighted MRI scan (Figure 1) demonstrated a mass with imaging characteristics consistent with soft tissue, which largely disappeared on the T2-weighted MRI scan (Figure 2). The axial CT scan (Figure 3) showed inhomogeneous opacification with a patchy "ground glass" appearance within the right sphenoid sinus. There appeared to be a bony shell over the anterior aspect of the lesion and no expansion or erosion of the cortical walls of the sinus.