FIG 1. Images from the case of a 54-year-old man with primary skull base amyloidoma.

A, High-resolution coronal temporal bone CT scan shows a permeated aspect of the normal bone of the basiocciput, with scattered foci of calcifications or remnants of destructed bone within. The lesion (asterisk) is centered on the right petro-occipital fissure (curved black arrow) and crosses the midline. The petro-occipital fissure on the opposite side (straight black arrow) is intact.

B, High-resolution axial temporal bone CT scan. A soft-tissue component (white arrows) extends through the posterior wall of the sphenoid sinus.

C, Sagittal spin-echo T1-weighted (840/12/3 [TR/TE/excitations]) MR image displays the lesion (arrows) as iso- to hypointense to muscle.

D, Coronal spin-echo T1-weighted (840/12/3) MR image.

E, Sagittal turbo spin-echo T2-weighted (4416/128/1) MR image shows the lesion affecting the clivus (arrows) with very low signal intensity, similar to that of the air in the sphenoid sinus (S).

F, Coronal contrast-enhanced spin-echo T1-weighted (840/12/3) MR image shows poor localized contrast enhancement (arrows).