HON-MAN LIUDAR-MING LAIYONG-KWANG TUWang, Yao-HungYao-HungWang2020-08-212020-08-2120051015-9770https://scholars.lib.ntu.edu.tw/handle/123456789/513452Background: We report a vascular abnormality of the middle cerebral artery (MCA) that has not been described in the literature before. Methods: Two patients (1 male and 1 female; age 44 and 67 years, respectively) were found to have a vascular abnormality in which the main trunk of the MCA had a twig-like form. Both patients presented with intracranial hemorrhage. Results: In these 2 patients, the abnormality was seen before the genu of the MCA. They had an intracranial hemorrhage due to an associated aneurysm inside the twigs. The twig appeared to be a network between the bifurcation of internal carotid artery and insular segment of MCA, and it was different from the collateral circulation due to acquired occlusion or moyamoya disease. Conclusion: This new type of vascular lesion of the MCA is not benign. It appears to be associated with the occurrence of an aneurysm, an important clinical aspect. Copyright ? 2005 S. Karger AG.en[SDGs]SDG3adult; aged; aneurysm; aneurysm surgery; article; brain hemorrhage; case report; clinical feature; clip; computer assisted tomography; female; human; insula; internal carotid artery; magnetic resonance angiography; male; middle cerebral artery; middle cerebral artery aneurysm; moyamoya disease; nerve cell network; nuclear magnetic resonance imaging; priority journal; three dimensional imaging; Adult; Aged; Female; Humans; Intracranial Aneurysm; Magnetic Resonance Angiography; Male; Middle Cerebral Artery; Tomography, X-Ray Computed; Treatment Outcomejournal article10.1159/000086119159258752-s2.0-22344438204