De novo formation of twig-like middle cerebral artery: An illustrative case

Abstract

Background: Twig-like middle cerebral artery (T-MCA) is a rare vascular abnormality characterized by the replacement of the M1 segment of the middle cerebral artery (MCA) with a plexiform arterial network of small vessels. T-MCA is generally regarded as an embryological persistence. Conversely, T-MCA may also be a secondary sequela but no reports of cases of de novo formation exist. Here, we report the first case describing possible de novo T-MCA formation. Case Description: A 41-year-old woman was referred to our hospital from a nearby clinic because of transient left hemiparesis. Magnetic resonance (MR) imaging revealed mild stenosis of the bilateral MCAs. The patient then underwent MR imaging follow-ups once a year. MR imaging at the age of 53 showed a right M1 occlusion. Cerebral angiography revealed a right M1 occlusion and formation of a plexiform network consistent with the occlusion site, leading to the diagnosis of de novo T-MCA. Conclusion: This is the first case report describing possible de novo T-MCA formation. Although a detailed laboratory examination did not confirm the etiology, autoimmune disease was suspected to have precipitated this vascular lesion.

Twig-like middle cerebral artery as a variety of isolated middle cerebral artery disease with new vessel formation: illustrative case

“… 12 , 13 No cases or evidence of acquired T-MCA formation have been reported so far, but the first case of de novo T-MCA formation was reported recently. 16 Our case is the second, and these cases indicate that acquired factors may be involved in the pathogenesis of T-MCA.…”

“…There is also a theory that it is an acquired abnormality for the following reasons. 16 1) Although cerebral hemisphere development requires the normal formation of the internal carotid artery and the MCA, patients with T-MCA have isolated abnormal changes in the M1 segment but typically develop cerebral hemispheres and a distal MCA. 13 2) Most twig-like patterns are found only in the proximal M1, but similar morphological changes have also been reported in the distal MCA.…”