PMC4524004_01
Preoperative Magnetic Resonance Images. (a) Axial T1-weighted image demonstrating lesion in the pineal region with evidence of early hydrocephalus. (b) Coronal contrast enhanced T1-weighted image showing an enhancing lesion extending inferiorly. (c) Sagittal contrast enhanced T1-weighted image demonstrating enhancing lesion displacing the quadrigeminal cistern and dorsal midbrain. (d) Axial FLAIR demonstrating moderate hyperintense lesion. (e) Axial T2-weighted image showing moderate hyperintense lesion. (f) Axial DWI showing moderate hyperintense lesion
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F1
The lesion appeared slightly hyperintense relative to cerebrospinal fluid (CSF) on T1-weighted images (WI) [Figure 1] and resulted in inferior displacement of the tectum causing partial obstruction of the aqueduct of Sylvius with associated dilation of the lateral and third ventricles.
Postoperative Magnetic Resonance Images (a) Axial T1-weighted MRI demonstrating normal postoperative changes. (b) Sagittal T1-weighted postcontrast MRI demonstrating normal postoperative changes
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F2
Follow-up MRI on postoperative day 3 demonstrated complete resection of the tumor [Figure 2].
Histology (a and b) Hematoxylin and eosin stained section demonstrating a moderately cellular neoplasm with highly pleomorphic, hyperchromatic nuclei. Frequent multinucleated and enlarged cells with giant, bizarre-shaped nuclei are present. Vessel walls are hyalinized and no areas of vascular proliferation or necrosis are noted. Rare mitotic figures are seen. (c and d) Photomicrograph of GFAP immunostaining demonstrating primarily focal positivity resembling a reactive process with discrete areas of diffuse positive staining. (e) Photomicrograph showing representative Ki-67 immunostaining. Cells show a low proliferation index with focal areas up to 1.6%. (f) Photomicrograph showing representative reticulin immunostaining. Staining can be seen in perivascular connective tissue but there is no reticulin network between the tumor cells. (g) Photomicrograph of Olig2 immunostaining demonstrating scattered positive cells. Magnification: x20 (h) Photomicrograph of synaptophysin immunostaining demonstrating a diffuse, strongly positive pattern. (i) Photomicrograph of Class III beta-tubulin immunostaining demonstrating a diffuse, strongly positive pattern
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F3
On hematoxylin and eosin stain [Figure 3], the tumor cells exhibited highly pleomorphic, hyperchromatic nuclei.