Unilateral proptosis: a diagnostic clinical and neuroimaging challenge

INTRODUCTION: The differential diagnosis of unilateral proptosis includes tumors, infections often related with immunological process, trauma, vascular diseases or axial myopia. CASE REPORTS: We present two patients with unilateral proptosis. A 34-yeard old caucasian man with a 3-months history of proptosis of the left eye with diplopia and normal visual acuity; initial CT scan examination showed highly suggestive finding for orbital apex tumor or glioma of the optic nerve, but a second CT scan with complementary projections was performed and a highly swollen inferior rectus muscle simulating an orbital apex tumor was visible. A diagnosis of unilateral thyroid ophthalmopathy was made. A 56-year old caucasian woman with unilateral exophthalmus and medical history of Graves’ hyperthyroidism; previously Graves’ ophthalmopathy was suggested. Fundoscopy showed myopic fundus. The CT scan revealed normal extraocular muscles without swollen. CONCLUSION: These two cases of unilateral proptosis are described because of their clinical and radiological differential diagnosis. We suggest that the accurate diagnosis of a unilateral proptosis remains a big challenge to the neuroophthalmologist, endocrinologist, immunologist, neurosurgeon and radiologist.