[Isolated hypertrophy of the superior oblique muscle in Basedow disease].

INTRODUCTION: Proptosis is the most common feature of Graves' ophthalmopathy. We report an exceptional case of proptosis in relation with an isolated enlargement of the superior oblique muscle in Graves' ophthalmopathy. OBSERVATION: After ocular contusion a 37 years old man presented a progressive right exophthalmos. On examination there was an unilateral proptosis with dilated conjunctival vessels, without any clinical signs of inflammation and no decreased vision. Ocular movements were full. On general examination signs of hyperthyroidism were present. CT-scan showed a superior oblique muscle enlargement with enlarged superior ophthalmic vein. Cerebral angiography excluded the diagnosis of a carotid-cavernous fistula. Dosage of thyroid hormone revealed hyperthyroidism. DISCUSSION: This case has a double interest: --Diagnostic: a CT-scan picture mimicking a carotido-cavernous fistula in this particular clinical context (history of ocular trauma, enlarged conjunctival vessels). --Isolated enlargement of superior oblique muscle in Graves' disease, which is exceptional in the literature.