A Case of Subarachnoid Hemorrhage with Dissecting Aneurysm of the Anterior Choroidal Artery

Dissecting aneurysms of the anterior choroidal artery (AchoA) are extremely rare, with only a few reported cases. Herein, we report an extremely rare case of subarachnoid hemorrhage with dissecting aneurysm of the AchoA. A 68-year-old man was hospitalized for sudden onset of headache, progressive consciousness disorder, and right hemiparesis. He had a prior medical history of systemic lupus erythematosus (SLE), and was taking prednisolone (50 mg/day) for 15 months. CT showed subarachnoid hemorrhage in the left side of the basal cistern and Sylvian fissure. Left internal carotid artery (ICA) angiography revealed a fusiform aneurysm of the AchoA. He was diagnosed with a ruptured dissecting aneurysm of the AchoA because the shape of aneurysm was fusiform and there was laminar flow inside the aneurysm. Parent artery occlusion (PAO) was performed to prevent re-hemorrhage on the day of onset. Although ventricular drainage for acute hydrocephalus was performed after AchoA occlusion, his consciousness disorder did not improve. Postoperative angiography at 1-week recovery from the procedure revealed disappearance of the AchoA, including the dissecting aneurysm. However, he died following septic shock caused by pneumonia at 1 month after the procedure. We report an extremely rare case of subarachnoid hemorrhage with a dissecting aneurysm of the AchoA. Vasculitis caused by SLE and a vulnerability of the vessel wall following chronic steroid use are potential causes of the dissecting aneurysm of the AchoA.