Thyroid ophthalmopathy: bony erosion on CT and increased vascularity on angiography.

A 21-year-old man had gradually increasing unilateral proptosis of the right eye . His history was remarkable in th at he had had a subtotal thyroidectomy several years earlier for Graves disease. He remained euthyroid on no thyroid medication and was, on admission, euthyroid with normal T3 and T4 . His vision had recently deteriorated from 20/ 20 to 20 / 50 00, but had return ed to normal when he was placed on steroid therapy. Physical examination was entirely normal, except for marked proptosis and marked conjunctival injection of the right eye. Plain films of the orbits were unremarkable. Optic canal tomograms were normal. Axial (fig . 1 A) and coronal (figs. 1 B and 1 C) CT scans revealed a slightly enhanc ing mass in the superior apex of the right orbit with evidence of smoothly marginated bone erosion on the posterior and superior wall of that orbit. There was obvious exophthalmus and thinning of the right orbital roof. The superior orbi tal mass appeared bilobed . The possibility of enlarged superior rectus and superior oblique musc les was entertained. Both medial rect i muscles appeared slightly prominent on the axial scans, but looked less enlarged on the coronal scans. Right external carotid arteriog raphy revealed no abnormalities. Right internal carotid arteriography (fig. 2) revealed stretching of the ophthalmic artery and its branches by a mass. A diffuse homogenous vascular stain , most prominent in the apex , was noted in the capillary phase along with many small irregular vessels. The increased vascularity and puddling perSisted somewhat into the venous phase. The left internal carotid angiog ram was normal. Because of the possibility of a solid tumor, a right frontal c raniotomy with extensive right orbital decompression was performed. Th e bony orbital roof was markedly thinned . The superior oblique and superior rectus muscles were hypertrophied to 8-10 times normal size. No tumor was found. A specimen was submitted for patholog ic study.