Abstract
Ruptured lateral posterior choroidal artery (LPChA) aneurysms are a quite rare pathogenesis of intraventricular hemorrhage (IVH). To our knowledge, most reported cases were associated with moyamoya disease. Our patient, however, showed neither moyamoya disease nor another anterior circulation occlusive disease. This 60-year-old man had sudden consciousness disturbance and was referred to our department. A CT scan revealed an IVH in the bilateral lateral ventricles and fourth ventricle. To investigate the bleeding origin, three-dimensional CT angiography was performed. However, no definite vascular lesion was found. On the admission day, evacuation of the IVH was done using an endoscope. In the subacute stage (17th day after onset), cerebral angiography revealed a right LPChA aneurysm without moyamoya disease. On the 26th day, under a navigation system, this aneurysm was trapped and excised using a transcortical (inferior temporal gyrus) and transventricular approach. In most reported cases, LPChA aneurysms were considered to be pseudoaneurysms secondary to the rupture of fragile collateral vessels of moyamoya disease. However, this case did not have associated moyamoya disease. In this case, we hypothesized the pathogenesis as follows. First, the usual microaneurysm that causes hypertensive intracerebral hemorrhage was generated on the LPChA without surrounding tissue compression. Under this condition, the microaneurysm was enlarged and finally collapsed in the lateral ventricle as a pseudoaneurysm without moyamoya disease.
