PMC8571199_01
Preoperative radiological images. CT-scan of the brain without contrast showed a sharply delineated cystic lesion located in the left dorsolateral pons (a). There appear some calcifications located in the anterolateral solid mass of the lesions. Contrast-enhanced T2-weighed MRI images again showing the hyperintense aspect of the cystic fluid (b). Limited edema can be noted at the dorsal side of the tumor. On the contrast-enhanced T1-weighted images, the tumor mass and part of the cyst wall enhanced homogenously (c).
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F1
Imaging studies showed a cystic tumor in the left dorsolateral pons [Figure 1].
Histopathological images. Following HE-staining, elongated spindle cells (arrow) are noted in the biopsy sections (a). Additional immunohistochemical staining revealed a strong positivity for S-100 protein (b) and pericellular basement membranes (arrows) of tumor cells following collagen IV staining (c). In figure 2D, a scattered neurofilament-positive intratumoral axons (arrows) can be seen. Based on these findings, the tumor was diagnosed as of intraparenchymal schwannoma Grade I. Original magnification x200 in all pictures, 100 mm scale bar.
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F2
Histological assessment of the tumor sections showed clusters of spindle cells surrounded by fascicles and palisades in addition to thick-walled vessels [Figure 2a]. Additional immunohistochemical examination exhibited positivity for S-100 protein, pericellular collagen IV basement membrane staining, and in some areas scattered few neurofilament (NF2F11) positive intratumoral axons [Figure 2b-d].