De novo twig-like middle cerebral artery documented by 13-year imaging surveillance and treated after hemodynamic compromise.

BACKGROUND: Twig-like middle cerebral artery (T-MCA) is a rare vascular anomaly characterized by stenosis or occlusion of the middle cerebral artery (MCA) with a plexiform network of collateral vessels, and its etiology, whether congenital or acquired, remains controversial. CASE DESCRIPTION: We report a rare case of de novo T-MCA identified as an acquired lesion through long-term imaging surveillance. A 54-year-old woman had undergone annual magnetic resonance (MR) imaging and MR angiography (MRA) follow-up after an initial transient neurological episode. Ten years later, progressive stenosis of the right MCA emerged. At 12 years and 3 months, she developed transient dysarthria and left hemiparesis, yet no infarction or hypoperfusion was noted, and observation was continued. At 13 years and 4 months, a second transient ischemic attack occurred. MRA revealed high-grade MCA stenosis with a cluster of abnormal vessels, consistent with T-MCA, and perfusion studies demonstrated impaired cerebrovascular reserve in the right hemisphere. Given the unstable hemodynamic profile, superficial temporal artery (STA)-MCA bypass was performed. Postoperatively, cerebral perfusion improved, and no further ischemic events were observed during 1 year of follow-up. CONCLUSION: To the best of our knowledge, this represents the third documented case of de novo T-MCA. This case provides important insight into the dynamic nature of T-MCA and suggests that, in symptomatic patients with recurrent ischemia and hemodynamic compromise, STA-MCA bypass may serve as a viable therapeutic strategy.