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Dural arteriovenous fistula - posterior fossa

Case contributed by Frank Gaillard
Diagnosis certain

Presentation

Tinnitus.

Patient Data

Age: 65
Gender: Male

A lobulated slightly hyperdense region is seen within the right side of the pons associated with prominent tortuous vessels in the cerebellopontine angle. 

There multiple abnormal tortuous vessels in the right ambient cistern, prepontine cistern, and right cerebellopontine angle likely representing veins draining a right posterior fossa dural AV fistula. A prominent varix indenting the right pontine hemisphere is noted, measuring 11 x 14 x 9 mm. 

Prominent draining veins into the right sigmoid sinus and right cavernous sinus are demonstrated. The cisternal portion of the right trigeminal nerve lies above the varix and its larger draining veins, but is related to smaller abnormal tortuous veins in the superior aspect of the right cerebellopontine angle.

The cavernous sinuses and superior ophthalmic veins appear normal. No direct impingement of the cisternal portions of either oculomotor nerve is demonstrated.

Brain parenchyma is otherwise unremarkable. There is no abnormal diffusion restriction or abnormal susceptibility related signal loss.

A dural arteriovenous fistula corresponding to the abnormality identified on MRI is noted within the posterior fossa to the right of midline. It receives multiple arterial branches from the right external carotid artery with the largest contribution seemingly from the enlarged ascending pharyngeal artery. Further branches from the internal maxillary artery are also noted.

Moderate contribution from meningohypophyseal arteries from the left ICA are also noted. There is a minor contribution from meningohypophyseal branches of the right internal carotid artery.

There is a small fistulous clump draining into a plexus of veins including a 12 mm venous varicosity. Drainage to multiple cortical veins is evident extending to the sigmoid sinus but also the deep system extending to the straight sinus.

Minimal contribution from the posterior circulation and none from left external carotid artery.

Case Discussion

This patient has gone to have embolization with substantial reduction in flow, and remains well on protracted followup. 

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