PMC6580896_01
Computed tomography on the day of admission showing diffuse subarachnoid hemorrhage.
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SAH (Figure 1).
Six-vessel angiogram (anteroposterior and lateral view) shows no aneurysm, arteriovenous malformation or fistula, dural sinus thrombosis, hypervascular tumor, or other vascular lesions. (A and B) right internal carotid artery, (C and D) left internal carotid artery, (E and F) right external carotid artery, (G and H) left external carotid artery, (I and J) right vertebral artery, and (K and L) left vertebral artery angiograms.
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She had experienced SAH of unknown vascular etiology 2 years earlier and had been observed at another hospital. Six-vessel digital subtraction angiography showed no aneurysm or abnormal vascularity (Figure 2).
(A) Follow-up computed tomography (CT) scan 2 days after onset showing residual subarachnoid hematoma in the right basal cistern. Magnetic resonance imaging scan at the level of the basal cistern, obtained 2 days after onset, demonstrating no intraparenchymal lesion or cisternal lesion on axial T1-weighted noncontrast (B), T1-weighted contrast (C), T2-weighted images (D). Fluid-attenuated inversion recovery image showing residual subarachnoid hematoma, consistent with the findings of the CT scan (E). In contrast, the balanced steady-state free precession image demonstrating the mixed-intensity reticular lesions in the left basal cistern (arrow) (F).
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CT and MRI were performed 2 days after onset. CT demonstrated only residual subarachnoid hematoma in the right basal cistern (Figure 3A). On T1-weighted, T2-weighted, and T1-weighted contrast-enhanced images, no parenchymal or cisternal lesion was apparent (Figure 3B-D). Fluid-attenuated inversion recovery images showed subarachnoid hematoma at the right basal cistern, as shown on CT (Figure 3E). However, the bSSFP sequence (fast imaging employing steady-state acquisition [General Electric, Milwaukee, Wisconsin, USA]) demonstrated mixed-intensity reticular lesions in the left basal cistern, while residual subarachnoid hematoma was not demonstrated (Figure 3F).
Intraoperative view obtained via the left pterional approach. The tan and gelatinous tumor occupying the left basal cistern. The hemorrhagic component was seen at basal cistern (white arrow) (A). High magnification intraoperative view indicating residual tumor (black arrowheads) involving the perforating artery originating from the ICA (white arrow) (B). The tumor is partially removed, and the middle cerebral artery, internal carotid artery, and left optic nerve are visible (C). Photomicrograph showing diffusely proliferated astrocytic cells with a microcystic space. Perivascular proliferation of tumor cells (arrow) is visible. Hematoxylin-eosin stain, x 200 (D). ACA, anterior cerebral artery; CN II, optic nerve; FL, frontal lobe; ICA, internal carotid artery; MCA, middle cerebral artery; TL, temporal lobe.
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The tumor occupied the left basal cistern and involved the left internal carotid artery (Figure 4A) and its perforating branches (Figure 4B), although the border between the tumor and the brain parenchyma was clear. A large part of the tumor anterior to the internal carotid artery and optic nerve, including the hemorrhagic component, was partially removed, because radical removal might have caused severe complications associated with injury of the perforating arteries (Figure 4C). Histopathological examination of the tumor showed a typical PA with a mixture of a compact fibrillary area and microcystic foci (Figure 4D).