Resolution of an anterior-inferior cerebellar artery feeding aneurysm with the treatment of a transverse-sigmoid dural arteriovenous fistula.

A 27-year-old man developed an unruptured anterior-inferior cerebellar artery (AICA) feeding aneurysm from a transverse-sigmoid dural arteriovenous malformation. The patient, with a known history of left transverse and sigmoid sinus thrombosis, presented with pulse-synchronous tinnitus. Angiography revealed an extensive dural arteriovenous fistula (AVF), with feeders from both the extracranial and intracranial circulations, involving the right transverse sinus, the torcula, and the left transverse/sigmoid sinuses. Multimodal endovascular and open surgical therapy was used to manage the lesion. Before a planned second-stage treatment for the left sigmoid sinus component, the dural AVF improved significantly. During this interval, however, a small flow-related aneurysm developed on the left AICA feeding the petrous dural region. The aneurysm resolved after resection of the involved sigmoid sinus. This is the first reported case of an unruptured feeding-artery aneurysm in an intracranial dural AVF that resolved spontaneously with treatment of the dural AVF. Until more is known about the natural history, the decisions of when and whether to treat an unruptured dural AVF feeding-artery aneurysm must be made on an individual basis.