A case report of an unruptured tectal AVM presenting with obstructive hydrocephalus that resolved upon spontaneous obliteration of the venous varix.

Cerebral arteriovenous malformations (AVMs) are complicated lesions representing a wide spectrum of pathology. They are frequently associated arterial aneurysms and venous varices, the latter of which carry a particularly high risk of rupture. AVM rupture commonly results in hydrocephalus, but there are a rare number of cases in which hydrocephalus develops as a result of an unruptured AVM. An elderly woman with a benign medical history presented to an outside hospital with 5 days of progressively worsening headaches that she described as retroorbital, dull, and lateralizing to the right. Workup at an outside hospital with a brain magnetic resonance image (MRI) and a head computed tomography angiogram (CTA) revealed concern for a tectal AVM with an associated venous varix abutting the tectal plate. Four weeks later, her headaches and diplopia had significantly improved. A diagnostic cerebral angiogram revealed that venous varix had decreased in size and a subsequent CTA showed interval improvement of her hydrocephalus. By the following month, her clinical signs and symptoms had completely resolved. Resolution of the patient's symptoms clearly correlated with multiple radiographic findings, and therefore it seems reasonable to assume that expansion of the varix was the inciting event that lead to the development of her symptoms. Although this case reflects an exceptional series of events, it helps emphasize the point that a shunt or a ventriculostomy may not be necessary in a patient presenting with hydrocephalus from an unruptured AVM.