Rete middle cerebral artery anomalies: a unifying name, case series, and literature review

Abstract

OBJECTIVE Rete middle cerebral artery (MCA) is extremely rare and has not been frequently discussed. Rete MCA is a weblike anomaly of the MCA that does not coalesce and forms a prominent, large single branch from the plexiform vessels in the fetal stage. The purpose of this study was to further elucidate the clinical and radiological characteristics of patients with rete MCA. METHODS A total of 2262 cerebral digital subtraction angiography procedures were performed on 1937 patients at the authors' institution from February 2013 to May 2017. Data analysis included age, sex, clinical symptoms, underlying diseases, coexisting cerebral arterial anomalies, and operative methods and findings. RESULTS Rete MCAs were found in 13 patients, and the incidence of this anomaly was 0.67% (13 of 1937) in this study. Of the 13 patients, 3 had hemorrhagic strokes, 6 had ischemic strokes, and 4 had no symptoms. Eight patients underwent conservative treatment, and 5 patients underwent surgical treatment. Rete MCA is considered a congenital disease of the cerebral vasculature with the possibility of an acquired abnormality, such as an aneurysm, caused by hemodynamic stress. Although an epidemiological survey of rete MCA was not conducted, it is assumed that rete MCA has a high prevalence in Asia. Ischemic and hemorrhagic stroke events are fairly common in rete MCA. CONCLUSIONS Clinicians should understand the radiological and clinical features of patients with rete MCA to avoid misdiagnosis and unnecessary treatment. This anomaly should be differentiated from other vascular diseases and patients presenting incidentally should be carefully monitored because of their vulnerability to both hemorrhagic and ischemic strokes.

Pediatric Stroke Associated with Rete Middle Cerebral Artery

“…Vascular study evidenced a plexiform appearance of the proximal M1 segment of the left middle cerebral artery (MCA), shown in Figure 2. These imaging findings were consistent with the diagnosis of rete MCA, a web-like anomaly previously described as unfused or twig-like MCA [1-3].…”

“…The etiopathology of rete MCA anomaly is unknown [2], although some authors consider it as a congenital disease, caused by failed fusion of the MCA during the fetal stage, which does not coalesce to form a single branch, therefore maintaining plexiform vessels [1]. An adult series of 13 cases of rete MCA found an incidence of 0.67%; it was asymptomatic in only 4 patients, with associated ischemic stroke in 6 cases and intracranial hemorrhage in 3 patients [1].…”

“…The optimal management of rete MCA has not been established yet [2]. Although some authors consider treatment unnecessary for asymptomatic patients [1,2], the association with stroke may require an intervention [1]. Patients with a hemorrhagic presentation are managed by clipping, burr hole or a bypass, while those with ischemic events may benefit from antiplatelets and a bypass [2].…”

“…Patients with a hemorrhagic presentation are managed by clipping, burr hole or a bypass, while those with ischemic events may benefit from antiplatelets and a bypass [2]. As the hemodynamic stress may result in an acquired abnormality such as aneurysms [1], long-term imaging follow-up is recommended, especially in children, considering the additional physical growth and increasing demand for cerebral blood flow.…”

“…Recognition of this anomaly is important in order to achieve a precise diagnosis and to determine the need for treatment [1]. Further studies are needed to determine the best treatment option for rete MCA.…”