Intraosseous Arteriovenous Malformation of the Sphenoid Bone Presenting with Orbital Symptoms Mimicking Cavernous Sinus Dural Arteriovenous Fistula: A Case Report
A 43-year-old female was referred to our hospital under the impression of a left CSDAVF. On presentation, she revealed left chemosis and proptosis that had developed ten days previously following several weeks of ipsilateral retroorbital pain and headache. She also had diplopia mainly due to ipsilateral abducens palsy. Brain magnetic resonance imaging (MRI) from the referring hospital showed a dark-signaled void lesion at the left paracavernous region and mild dilatation of the ipsilateral cavernous sinus and superior ophthalmic vein.\nOn physical examination, her right lower leg was hypertrophied with a geographic pattern of bluish cutaneous stains (). No vascular bruit was audible in the limb and she had no complaints about her leg. There was no family history of note, including no history of vascular malformations. We diagnosed our patient as KTS basis on her features.\nAngiography showed a triangular-shaped vascular chamber fed by multiple feeders of the left external carotid artery (ECA) especially from the terminal branches of the left internal maxillary artery and accessory meningeal artery (). The vascular chamber drained via the ipsilateral cavernous sinus with significant reflux into the ipsilateral superior and inferior ophthalmic veins while the inferior petrosal sinus was patent (). No additional feeder was noted on internal carotid injections and right external carotid angiography. A subsequent right femoral arteriogram showed no vascular abnormalities in her hypertrophied lower leg.\nA retrospective review of her brain MRI showed that the vascular mass corresponded with the dark-signaled mass in the left side of the sphenoid body and the medial aspect of the greater wing (). Subsequent contrast-enhanced computed tomography (CT) revealed an osteolytic space of densely enhancing vascular chamber surrounded by a sclerotic bony margin, consistent with imaging findings of an intraosseous AVM ().\nWe performed endovascular treatment with Onyx (EV3, Irvine, CA, USA) embolization to relieve her orbital symptoms. The patient was placed under general anesthesia and was heparinized. Vascular access was obtained with a 5F guiding catheter (Envoy, Cordis, Miami Lakes, FL, USA). On the super-selective angiograms of the major feeders, we found that the feeders near the vascular chamber consisted of numerous fine arteries rather than sizeable fistulas. The left accessory meningeal artery was catheterized with a dimethysulfoxide (DMSO)-compatible microcatheter (Rebar 14, EV3, Irvine, CA, USA), which was advanced to be sited in the prenidal position and successfully wedged. Following successful solidification of the reflux, the liquid embolic material (Onyx 18, EV3, Irvine, CA, USA) was injected slowly until it started to fill the draining vein. Three bottles of Oynx were injected. The post-embolization angiogram showed prominent reductions in vascularity and degree of AV shunting. The patient awakened from general anesthesia without any neurologic deficits. She was maintained on low-molecular-weight heparin during the postprocedural period. Her eye symptoms gradually resolved over 3 days and she was discharged without any complications. A 3-month follow-up angiogram demonstrated complete obliteration of the AVM ().