A case of aplastic or twig-like middle cerebral artery associated with a ruptured A1 aneurysm at the origin of the anomalous collateral artery

Aplastic or twig-like middle cerebral artery harboring unruptured cerebral aneurysms treated by clipping and bypass surgery: illustrative case

“…There are several reports of parent artery occlusion by intravenous embolization of the ruptured aneurysms in patients with Ap/T-MCA. 2,14 Aneurysms that developed inside the plexiform network may differ from common saccular aneurysms; the vessels that form plexiform networks themselves may show aneurysmal dilation, as in our case. It may be unavoidable to sacrifice the parent vessel in some cases, but maintaining blood flow to the distal portion is especially important in conditions such as Ap/T-MCA, in which hemodynamic stress is involved.…”

“…6 To the best of our knowledge, approximately 60 cases of Ap/T-MCA have been reported so far. [1][2][3][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Of these, 26 cases were associated with aneurysms, including ours (Table 1), with 19 ruptured and 7 unruptured cases. The average age (26 cases) was 54.2 years, and women were more likely to be affected.…”

“…1,3,6,11 Approximately 70% of patients with Ap/T-MCA develop hemorrhagic stroke, 20% develop ischemic stroke, and only a few are asymptomatic. [1][2][3][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] These symptoms and hemodynamics resemble moyamoya disease (MMD). Patients with Ap/T-MCA who have hemorrhagic stroke often have aneurysms, as seen in 23 of 31 (74.2%) previously reported hemorrhagic stroke cases.…”

“…Patients with Ap/T-MCA who have hemorrhagic stroke often have aneurysms, as seen in 23 of 31 (74.2%) previously reported hemorrhagic stroke cases. [1][2][3][6][7][8][9][10][11][13][14][15][16][17][18][19][20][21][22] In these patients, the optimal treatment remains controversial because it is necessary to consider both the aneurysm location and hemodynamic stress effect due to vascular malformation.…”

A Ruptured Aneurysm in Aplastic or Twig-like Middle Cerebral Artery: A Case Report with Histological Investigation

“…Most articles on Ap/T-MCA were published from East Asia, such as Korea and Japan. 2,6,7) The pathogenesis of Ap/ T-MCA is not yet well known. During embryonic development, the trunk of the MCA is formed by the fusion and regression of numerous plexiform arterial twigs that arise just distal to the anterior choroidal artery.…”