[Unilateral cavernous angioma of the thalamus disclosed by transitional disorders in the upward gaze].

We describe a case of a cavernous angioma of the right thalamus, identified by MRI, showing transient vertical diplopia in the upward gaze, present only in protracted recumbency. We consider possible pathogenetic mechanisms in an attempt to explain this peculiar disturbances. In addition we emphasize that MRI is the most sensitive procedure for detection of the cavernous angioma.