Extradural spinal arteriovenous fistula - type 2

Case contributed by Dr Chris O'Donnell


Has worsening pain in the right side of the upper abdomen. No obvious neurological deficit. Incidental finding on CT abdomen.

Patient Data

Age: 20 years
Gender: Male

CT scan abdomen performed to diagnose abdominal pain


Enhancing extradural mass lesion eroding the right lamina of L1and encroaching on the spinal canal.

MRI performed for clarification including dynamic TWIST sequence for assessment of feeding vessels


T1 and T2 hypointense mass at the site of CT abnormality consistent with flow void.  Note bright signal on the gradient (white blood) sequences.   No spinal cord swelling or T2 brightening to indicate cord ischemia.  Large extradural venous filling early in the arterial phase of the TWIST sequence with large draining epidural veins especially to the right entering the hemiazygos vein.  Note no vascular lesion within the dura.  Appearnace are typical for AV fistula.  It is all extradural and in this case erodes bone.

Case Discussion

Extradural AVF should not be confused with the more common and potentially more symptomatic dural AVF that is located inside the dura and can be associated with cord ischemia and hemorrhage.  These rare extradural lesions may be an incidental finding but can be symptomatic by way of mass effect of the distened veins on the foraminal nerve roots or spinal cord.  There are 2 types; 1 having an intradural component and 2 being entirely extradural (A producing mass effect on the cord and B showing no mass effect).

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.