PMC8053450_01
PMC8053450_02
(a) Interictal electroencephalogram (EEG), with an averaged reference, reveals periodic discharges with a predominant negative component occurring once every 1-4 s in the left and mid-occipital region (O1 and Oz of the International EEG 10-20 system, respectively, red asterisks). (b) Ictal EEG, with the twitching of bilateral eyelids, demonstrates rhythmic slow waves originating from the occipital region (O1, O2, and Oz, blue arrows). (c) Preoperative axial-view of T1-weighted (Gd) administration shows an isointensity tumor in the right cerebellum protruding into the 4th ventricle. No Gd enhancement was noted. (d) The tumor is presented in an isointense on preoperative axial view of image with fluid level attenuated inversion recovery sequences. (e) Fusion image of 18F-fluorodeoxyglucose positron emission tomography and computed tomographic scan, at the level comparable to the panel (c), depicts hypermetabolism of the tumor.
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F1
International EEG 10-20 system, respectively) [Figure 1a]. Ictal EEG demonstrated rhythmic slow waves originating from the occipital region (O1, O2, and Oz) [Figure 1b]. MR images demonstrated an isointense tumor, with a size of 15 x 16 x 23 mm (same size as MR images at the age of 3 days) in the right cerebellum protruding into the 4th ventricle [Figure 1c and d]. No gadolinium enhancement was noted. 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) showed hypermetabolism of the tumor [Figure 1e].
(a) Intraoperative photograph shows that a tumor (blue arrows) protruding into the 4th ventricle is exposed through the transcerebellomedullary fissure approach. (b) A depth electrode with 3 contacts (yellow arrow) is inserted into the tumor, and a strip electrode (red arrow) is placed on the cerebellar surface. (c) Intraoperative depth electroencephalogram (EEG) recording from the tumor, with A1 reference, depicts periodic discharges with a positive-negative configuration occurring once every 1-4 s. The periodic discharges show maximum amplitude at a depth of 10 mm from the tumor surface (red asterisk), with a slight decrease in amplitude at 5 and 15 mm depths. (d) Time-frequency analysis (short-term fast Fourier transformation) for the EEG at a depth of 10 mm from the tumor surface (red asterisk) demonstrates high frequency oscillatory activity around 80-100 Hz (ripple range), riding on the periodic discharges. Color coordinates were constructed on a logarithmic scale (-1.0 to 1.0). (e) No paroxysmal discharge was recorded from the cerebellar surface. (f) Following the resection of three-quarters of the tumor, the tip of the depth electrode was inserted again into the remnant tumor. EEG demonstrates the disappearance of paroxysmal activity from the remnant tumor. (g) No paroxysmal discharge was noted on the cerebellar surface as was observed before resection of the tumor. (h) Postoperative T1-weighted magnetic resonance image demonstrates that the tumor was subtotally resected except for the tumor around the right facial colliculus (yellow arrow). (i and j) Histopathological findings of the tumor with hematoxylin and eosin staining (i) and immunostaining for neuronal nuclei (NeuN) (j). The tumor consists of irregular clustering of NeuN-immunopositive ganglion cells without a glioma component.
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F2
Histopathologically, the tumor consisted of irregularly clustered neuronal nuclei (NeuN) immunopositive ganglion cells without a glioma component, indicating gangliocytoma [Figures 2 i and j].
PMC8053450_03
(a) Intraoperative photograph shows that a tumor (blue arrows) protruding into the 4th ventricle is exposed through the transcerebellomedullary fissure approach. (b) A depth electrode with 3 contacts (yellow arrow) is inserted into the tumor, and a strip electrode (red arrow) is placed on the cerebellar surface. (c) Intraoperative depth electroencephalogram (EEG) recording from the tumor, with A1 reference, depicts periodic discharges with a positive-negative configuration occurring once every 1-4 s. The periodic discharges show maximum amplitude at a depth of 10 mm from the tumor surface (red asterisk), with a slight decrease in amplitude at 5 and 15 mm depths. (d) Time-frequency analysis (short-term fast Fourier transformation) for the EEG at a depth of 10 mm from the tumor surface (red asterisk) demonstrates high frequency oscillatory activity around 80-100 Hz (ripple range), riding on the periodic discharges. Color coordinates were constructed on a logarithmic scale (-1.0 to 1.0). (e) No paroxysmal discharge was recorded from the cerebellar surface. (f) Following the resection of three-quarters of the tumor, the tip of the depth electrode was inserted again into the remnant tumor. EEG demonstrates the disappearance of paroxysmal activity from the remnant tumor. (g) No paroxysmal discharge was noted on the cerebellar surface as was observed before resection of the tumor. (h) Postoperative T1-weighted magnetic resonance image demonstrates that the tumor was subtotally resected except for the tumor around the right facial colliculus (yellow arrow). (i and j) Histopathological findings of the tumor with hematoxylin and eosin staining (i) and immunostaining for neuronal nuclei (NeuN) (j). The tumor consists of irregular clustering of NeuN-immunopositive ganglion cells without a glioma component.
SNI-12-98-g002.jpg
PMC8053450_03_SNI-12-98-g002.jpg
F2
Histopathologically, the tumor consisted of irregularly clustered neuronal nuclei (NeuN) immunopositive ganglion cells without a glioma component, indicating gangliocytoma [Figures 2 i and j].