Article révisé par les pairs
Résumé : A 60 year-old woman complaining of diplopia presents an ocular motility disturbance mimicking internuclear ophthalmoplegia. Idiopathic dermatomyositis is diagnosed by the help of clinical, biological, electrophysiological and histological data. The outcome is favorable under corticotherapy. Ocular muscle involvement is rare in dermatomyositis. An overlap syndrome with another auto-immune disorder like myasthenia should be excluded in this kind of manifestation.