PMC5299148_01
Axial computed tomography (CT) (a) and magnetic resonance imaging (MRI) scans (b-d, f) and coronal MRI scan (e). (a) CT scan shows a low-density lesion in right insular cortex with no calcification. (b) T1-weighted MRI demonstrates a hypointense lesion. (c) T2-weighted MRI shows a hyperintense lesion that corresponds with the hypointensity on the T1-weighted MRI image. (d, e) T1-weighted MRI with gadolinium administration did not demonstrate any enhanced lesion. (f) Arterial spin labeling study shows decreased blood flow at the lesion
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F1
Computed tomography (CT) imaging showed a low-density lesion with no calcification located in the right insular cortex [Figure 1a]. T1-weighted MRI demonstrated a hypointense lesion in the right insular cortex [Figure 1b]. T1-weighted image [Figure 1c]. T1-weighted MRI with gadolinium administration did not show any enhanced lesions [Figure 1d and e]. Arterial spin labeling study suggested decreased blood flow at the lesion [Figure 1f].
(a-d) T2-FLAIR MRI scans in the axial plane from age 8 to 18 years show gradual growth. An inserted picture in the corner of images is a three-dimensional reconstructed model of the tumor in each figure. (e) A dot graph with an almost straight line shows that the increase in tumor volume is directly proportional to time
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F2
The lesion located in the right insular cortex demonstrated gradual growth for 10 years [Figure 2a-d]. The growth rate of this lesion was found to be almost directly proportional to time [Figure 2e].
Intraoperative (a) and postoperative (b) images. (a) Intraoperative view after tumor resection during awake surgery. Tag 1 suggests the area where anarthria was induced on the ventral precentral gyrus by direct electrical stimulation. An inserted picture is the three-dimensional cortical view. (b) Fluid-attenuated inversion recovery magnetic resonance imaging performed 3 months after the operation shows gross total resection. Arrows indicate the Sylvian fissure
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F3
An anarthria was induced by stimulation of the ventral precentral gyrus [Figure 3a]. A postoperative MRI showed gross total resection of the tumor [Figure 3b].
Photomicrographs of the surgical specimen showing the hypointense lesion on T1-weighted magnetic resonance imaging. (a) Multiple cystic structures are observed on a mucinous background. Hematoxylin and eosin (H and E) staining, original magnification x100. (b) High-power view of a, showing floating neurons (arrows) scattered in the cystic structure. H and E staining, x200. (c) Negative staining for IDH1 mutation, x100. Inset: Positive control (d) The Ki-67 staining index was 1%, x100
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Histological examination of the hypointense area on T1-weighted MRI showed multiple cystic structures with myxomatous background and proliferation of oligodendroglia-like cells with oval nuclei in the wall of the cystic spaces [Figure 4a]. Neuronal elements featuring "floating neurons" were observed, indicating a glioneuronal lesion within the cystic cavity [Figure 4b]. Immunohistochemical analysis revealed intense positive staining for Olig2, S-100 and synaptophysin, and less reactivity for IDH-1 [Figure 4c]. The Ki-67 staining index (SI) was 1% [Figure 4d].