PMC8168793_01
(a) Axial view showing corpus callosum lesions (b and c) sagittal T2 FLAIR images showing corpus callosal lesions and periventricular lesions oriented perpendicular to long axis of lateral ventricle (d) ovoid periventricular lesion (e and f) coronal T1 + contrast and axial T1 + contrast demonstrating absence of lesions.
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F1
Brain MRI revealed T2 FLAIR hyperintense lesions involving the body of the corpus callosum and the periventricular white matter without contrast enhancement, suggestive of demyelinating plaques [Figure 1].
(a) Axial T2 FLAIR showing worsening of previously noted corpus callosum lesion (b) axial T2 FLAIR showing an ovoid 3rd ventricular mass, obstructive hydrocephalus, and periventricular T2 hyperintensity (c) sagittal T2 image showing worsening of previously noted periventricular lesions (d) T1 axial post contrast scan showing homogenous enhancement of 3rd ventricle mass.
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F2
MRI of his brain demonstrated an intraventricular mass located in the posterior third ventricle, obstructive hydrocephalus and worsening of corpus callosum and periventricular T2 hyperintense lesions [Figure 2].
(a and b) are low- and high-magnification. (c) is cytologic preparation during intraoperative consultation. Prominent nucleoli are highlighted by arrows in (b and c). (d-f) are immunohistochemistry for OCT3/4, CD117, and H3 K27M respectively. Original magnification for (a) is x20, (b) and (c) are x60, (d) to (f) are x40.
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F3
The cytoplasm was pale in some areas [Figures 3a and b] but was more eosinophilic in other areas. Prominent nucleoli were noted in many of the tumor cells [Arrow in Figures 3b and c] and were best appreciated in the cytologic preparation obtained during intraoperative consultation. The tumor cells were positive for OCT3/4 [Figure 3d], CD117 (c-kit) [Figure 3e], placental alkaline phosphatase, cytokeratin AE1/AE3, and cytokeratin 7. The tumor cells were negative for H3 K27M [Figure 3f], glial fibrillary acidic protein, Olig2, IDH1-R132H, synaptophysin, Sox10, Melan-A, CD30, thyroid transcription factor 1, and thyroglobulin.
Axial and coronal T2 FLAIR showing corpus callosum and periventricular lesions which are decreased in size as compared to Figure 2 and resolution of hydrocephalus.
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F4
T2 hyperintense changes (thought to possibly be related to trans-ependymal flow initially) and decrease in size of corpus callosum plaques [Figure 4]. To rule out paraneoplastic optic neuritis, serum studies were performed and common markers for the disease, anti-CRMP-5, and anti-amphiphysin, were both negative.