Background: It is all occasional giant case we came to recently. The young patient had no special presentation except for transient epilepsy. It was difficult to get the first impression with either CT or MRI because the mass was huge that it was difficult to locate where its root was. A careful DSA examination further gave us a probable diagnosis-AVF, which was identified through Surgery. According to our literature work on PUBMED, few cases have ever been reported with such giant size. Case Description: A 23-year-old man presented with transient epilepsy, and routine computer topography scan only showed a giant mass with clear rounding edge, about 9 cm in diameter, significantly enhanced with contract. The radiologist's diagnosis was an intracranial aneurysm. A draining vein connecting to the superior sagittal sinus was discovered on DSA, which further confirmed the AVF. A tough yet successful operation was performed to totally remove the intracranial mass, and the patient recovered to normal. Conclusion: The widely accepted treatment of AVF includes endovascular coiling, surgical resection, burning or blockage of the fistulae, or the combination of endovascular and surgical treatments. Comparing to general cases, the size of the AVF in our case is rare. We successfully surgically removed the giant mass, and-the patient has totally recovered. (C) 2009 Elsevier Inc. All rights reserved.