Focal orbital amyloidosis presenting as rectus muscle enlargement: CT and MR findings.

We report a case of focal orbital amyloidosis involving rectus muscles, which is an extremely rare clinical condition. CT scans showed rectus muscle enlargement with punctate calcifications. Heterogeneous hypointensity was present on T2-weighted MR images, and homogeneous enhancement was seen on fat-saturated contrast-enhanced images of the muscles. These imaging findings seem to be suggestive of amyloidosis. Focal amyloidosis should be included in the differential diagnosis of extraocular muscle enlargement.