This 37 y/o male was referred for maxillofacial and orbital CT with a history of recent onset of facial and eye pain with left unilateral exophthalmus. Selected axial and coronal CT images shown above demonstrate left unilateral exophthalmus and hypertrophy of the muscles of oculation on the left. The medial rectus demonstrates thickening of the muscle belly with relative sparing of the muscle ends. Medial and inferior rectus are relatively more involved than superior and lateral rectus. The findings are consistent with early unilateral Graves' ophthalmopathy. TSH was found to be decreased consistent with the diagnosis. Incidental note was made of sinusitis of the maxillary sinuses right greater than left, with a mucous retention cyst on the left.