PMC5767480_01
(A) Axial T2-weighted magnetic resonance image (MRI) showing a large iso- to hyperintense tumor in the trigone of the left lateral ventricle, associated with peritumoral brain edema and a moderate midline shift to the right. The posterior horn of the lateral ventricle is entrapped. (B, C) Axial and coronal T1-weighted MRI with gadolinium, respectively, showing almost homogeneous tumor enhancement. The white arrow indicates the trajectory followed for tumor resection in the first and the second surgeries. (D) Raw magnetic resonance angiography (MRA) images showing feeders ascending to the antero-inferior surface of the tumor (arrowheads). The open circle indicates the target point for feeder occlusion, and the arrow indicates the trajectory followed to the target. (E) MRA image (axial view) showing the dilated left anterior choroidal and left lateral posterior choroidal arteries. (F) Left carotid angiogram (lateral view) showing feeders originating from the left anterior choroidal artery (arrow). (G) Left vertebral angiogram (lateral view) showing feeders originating from the left lateral posterior choroidal artery (arrow).
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F1
T2-weighted images. There was marked peritumoral brain edema in the left temporal and parietal lobes associated with a midline shift to the right, and the posterior horn of the left lateral ventricle was entrapped (Fig. 1A). The tumor showed almost homogeneous enhancement with gadolinium (Figs. 1B and 1C). Raw magnetic resonance angiography (MRA) images showed the feeders ascending on the antero-inferior surface of the tumor (Fig. 1D). MRA images also showed that both the left anterior choroidal and left lateral posterior choroidal arteries were dilated (Fig. 1E). Cerebral angiograms revealed that the anterior quarter of the tumor was fed by the anterior choroidal artery, while the remaining three posterior quarters were fed by the lateral posterior choroidal artery (Figs. 1F and 1G). Through the trajectory, the feeders originating from the anterior choroidal and lateral posterior choroidal arteries were identified on the antero-inferior surface of the tumor (Fig. 1D).
(A) Histologic features of the tumor observed at the first surgery, showing abundant collagen fibers and mildly swollen spindle-shaped tumor cells compatible with transitional meningioma (hematoxylin and eosin stain, x100, original magnification). (B) Histologic features of the tumor observed at the second surgery, showing an ischemic scar consisting of extensive fibrosis, hyalinization, and few tumor cells (hematoxylin and eosin stain, x100, original magnification).
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F2
The formalin-fixed tumor specimens showed mildly swollen and proliferating spindle-shaped tumor cells associated with abundant collagen fibers (Fig. 2A). Histological examination of the specimens in the second surgery showed extensive fibrosis and hyalinization without tumor cells, which were consistent with coagulation necrosis (Fig. 2B).
(A) Axial T1-weighted magnetic resonance image (MRI) with gadolinium acquired 3 days after the first surgery showing only marginal enhancement of the residual tumor, suggesting that tumor infarction has been induced widely. (B) Axial T1-weighted MRI with gadolinium acquired 1 year after the first surgery showing a remarkable decrease in the volume of the residual tumor (a 20% decrease in diameter) associated with resolution of the midline shift. An increased contrast enhancement area suggests revascularization of the residual tumor. (C) Left carotid angiogram (lateral view) just before the second surgery showing that feeders originating from the left anterior choroidal artery had been obstructed. (D) Left vertebral angiogram (lateral view) just before the second surgery showing remaining or newly developed small feeders originating from the left lateral posterior choroidal artery (arrow). (E) Axial T1-weighted MRI with gadolinium acquired 6 days after the second surgery, showing the remaining medial half of the tumor. (F) Axial fluid-attenuated inversion recovery image acquired 6 days after the third surgery performed by using the high parietal approach, showing complete resection of the tumor.
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F3
MRI with gadolinium acquired 3 days after the surgery showed enhancement only at the margin of the residual tumor, suggesting that tumor infarction was widely induced (Fig. 3A). The increased area of contrast enhancement suggested revascularization of the residual tumor (Fig. 3B). MRI acquired 6 days after the second surgery showed that almost half of the tumor had been removed (Fig. 3E). The lateral ventricle was then penetrated and the residual tumor was totally removed in a piecemeal fashion with a total blood loss of 270 mL (Fig. 3F).