PMC4533421_01
A: A computed tomography (CT) scan on admission revealed a diffuse subarachnoid hemorrhage with an intracerebral hematoma in the left putaminal area. B: A three-dimensional CT angiogram (3D-CTA) showed left middle cerebral artery (MCA) hypoplasia and an anomalous branch of the anterior choroidal artery (telencephalic branch), which shared in supplying the left MCA territory, and no obvious aneurysmal shadow. C: Serial digital subcutaneous angiography showed an aneurismal shadow located at the collateral artery that extended from the proximal A2 segment to the M1 segment. D: Follow-up 3D-CTA showed the growth of the aneurysm. E: A schematic illustration showed the angiographical findings in detail (arrows: a collateral artery that extended from the proximal A2 segment to the aneurysm, arrowhead: a collateral artery that extended from the proximal A1 segment to the aneurysm, asterisk: the left MCA hypoplasia). Acho: anterior choroidal artery, Lt: left.
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A three-dimensional computed tomography angiograph (3D-CTA) showed left MCA hypoplasia and an anomalous branch of the anterior choroidal artery (telencephalic branch), which shared in supplying the left MCA territory, and no obvious aneurysmal shadow (Fig. 1B, E). A2 segment to the M1 segment (Fig. 1C, E; arrowhead and arrows). A follow-up 3D-CTA showed the growth of the aneurysm (Fig. 1D). A schematic illustration showed the angiographical findings in detail (Fig. 1E).
A left frontotemporal craniotomy was performed. An intra-operative photograph and three dimensional computed tomography angiogram showed the left ICA and the MCA hypoplasia with an anomalous branch of the anterior choroidal artery (Acho), which shared the left MCA territory (A, B, D; asterisk). After the dissection of the chiasmatic cistern, we confirmed the abnormal vessels from the M1 to the aneurysmal shadow (E; arrowhead), traced the ACA, and observed the collateral artery that extended from the proximal A2 segment to the M1 segment (G; arrows). With the further retraction of the frontal lobe, we were able to trace the abnormal artery to reach the encapsulated old clot hematoma, including the aneurysm (H; dotted line). The area around the encapsulated hematoma was completely dissected and thereafter trapped successfully (I). A schematic illustration showed the intraoperative findings in detail (C, F, J; arrow: a collateral artery that extended from the proximal A2 segment to the aneurysm, arrowhead: a collateral artery that extended from the proximal A1 segment to the aneurysm, asterisk: the left MCA hypoplasia, dotted line: the encapsulated old clot hematoma, including the aneurysm). ACA: anterior cerebral artery, ICA: internal cerebral artery, MCA: middle cerebral artery.
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ICA (Fig. 2A), and observed that the left MCA hypoplasia (Fig. 2A, C, D, F, J; asterisk) with an anomalous branch of the anterior choroidal artery (telencephalic branch) shared the left MCA territory. In addition, the collateral artery that extended from the proximal A2 segment to the M1 segment could be viewed (Fig. 2E, F; arrowhead), and was traced toward the aneurysm (Fig. 2C, G, J; arrows). With further retraction of the frontal lobe, the encapsulated old clot hematoma, including an aneurysm, was confirmed (Fig. 2H, J; dotted line). The area around the encapsulated hematoma was completely dissected and trapped successfully (Fig. 2J; black line).
Photomicrograph of the excised pseudoaneurysm showed the aneurysmal wall consisted of a fibrin layer, which was laminated and intermingled with blood clot elements. Fresh and old thrombus were adherent to the inner surface of the pseudoaneurysmal wall.
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The aneurysmal wall consisted of a fibrin layer, which was laminated and intermingled with blood clot elements (Fig. 3) without inner reticular layer.