Ruptured aneurysm associated with a twig-like middle cerebral artery: An illustrative case report

Abstract

Background: Anomalies of the middle cerebral artery (MCA) are rare; among the different types of anomalies, the aplastic or twig-like (Ap/T) MCA is extremely rare and has been reported under various names, including aplastic, unfused, or rete type anomaly. The occurrence of a brain aneurysm associated with this anatomic variant is an even rare event, and probably their development and rupture are related to hemodynamic stress of the tinny wall of vessels forming the network. Case Description: We present a 43-year-old male patient with an explosive and persistent right orbitofrontal headache. A computed tomography showed a right frontobasal hematoma with intraventricular disruption. Magnetic resonance angiography showed a right MCA aneurysm and what seems to be a MCA trunk stenosis. Cerebral digital subtraction angiography demonstrated a plexiform arterial network and one aneurysm arising from the network. The patient was successfully treated by surgical clipping to evacuate the hematoma and to prevent further intracranial hemorrhages. Conclusion: The Ap/T-MCA may be associated with hemodynamic stress with a significant effect through the tinny wall of the vessels causing hemorrhage or leading to the formation and rupture of cerebral aneurysms. Based on a correct diagnosis of the anomaly, treatment can be completed successfully through different standard methods.

Case report: Endovascular coil embolization of an aneurysm at the origin of the accessory middle cerebral artery from the A1 segment as the collateral artery to twigs

“…In our case, the main suppliers included AccMCA and AchA ( Figure 2 ). With the AccMCA as a collateral artery of the twig-like MCA, an aneurysm can occur at its origin ( 31 ). Associated aneurysms are reported in nearly 40% of cases of twig-like MCAs, suggesting hemodynamic stress and structural vulnerability, and the aneurysms can be inside or outside the twig ( 3 , 30 , 32 ).…”

“…In the Serrano-Rubio et al review in 2022, there were 42 cases in the international literature of aneurysms associated with twig-like MCAs, most of which were ruptured ( 31 ). In this report, although cases of aneurysms at the origin of the AccMCA were collected, the review was not as extensive.…”

Rete Middle Cerebral Artery Aneurysm: A Case Report and Systematic Review

“…Hemodynamic and wall shear stress are considered the main pathophysiological mechanism of aneurysm formation in the twig-like vessel. 13 15 The adult MCA can relieve the pressure from the internal carotid artery, but the arterial twigs are usually thinner and the muscular layer is less developed, leading to structural fragility and flow-related aneurysms. 2 The main differential diagnoses of rete MCA are moyamoya disease and moyamoya syndrome.…”

“…Including ours, only 22 cases with a good description have been reported in the English literature, with a total of 28 rete MCA aneurysms ( Table 1 ). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Table 1 presents a summary of rete MCA aneurysms, enabling a comparison between T-MCA and T-NACA aneurysms. The average age of patients is 56.1 years, with no gender prevalence (11/22, 50%).…”

Ruptured pial-pial collateral aneurysm associated with left internal carotid artery occlusion: nuances of surgical management. Illustrative case

“…A review of aneurysms arising from a collateral network from nonmoyamoya occlusion, similar to our patient's presentation, revealed only 13 previously reported cases. 2,[5][6][7][8][9][10][11][12][13] None of these were associated with occlusion of the ICA. Although the occurrence of STA-OA anastomosis is reported infrequently, 14 pial-pial vascular network aneurysms are exceedingly rare.…”