[Arteriovenous malformation of the orbit].

Arteriovenous malformation is a rare vascular disease of the orbit that has to be differentiated from arteriovenous fistulas (e.g., of the carotid sinus), arterial aneurysms, the varices and the angiomas. It develops in the presence of an underlying constitutional maldifferentiation of the vascular bed but usually only becomes manifest in early adulthood. Typical clinical signs are exophthalmos, often with pulsation and thrill; episcleral and conjunctival vascular congestion; secondary glaucoma; and, to varying degrees in the late stage, restricted movement with double images as well as functional losses. The therapeutic measures otherwise routinely applied for such vascular deformities - e.g., surgical excision or, even better, embolization - have to be handled with ease in the orbit, since these vascular convolutions are also supplied in all cases by the ophthalmic artery. Two typical cases are presented to illustrate the clinical picture, diagnosis, differential diagnosis, and treatment possibilities.