PMC7749960_01
Preoperative images. Axial (a) and coronal (b) noncontrast CT image showing the hypodense cerebellopontine mass extending in the supratentorial space, interpeduncular and ambiens cisterns, and the right Meckel's cave. (c and d) T1- and T2-weighted coronal MRI showing the extent of the tumor. (e) 3D-FIESTA sequence indicating the extension of the tumor into the internal acoustic canal. (f) Axial diffusion-weighted imaging demonstrating intermediate diffusion signal when compared with CSF. (g) Coronal view of T1-weighted with gadolinium demonstrating faint tentorial enhancement and no enhancement within the tumor. (h) Coronal view of a contrasted CT demonstrating the tentorial enhancement.
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F1
Noncontrast CT of the head revealed a hypodense right cerebellopontine angle mass extending from the interpeduncular and ambient cisterns to the foramen magnum [Figure 1a and b]. There was compression of the brainstem with effacement of the fourth ventricle but no hydrocephalus [Figure 1]. T2-weighted hyperintense mass [Figure 1c and d]. The three-dimension fast imaging employing steady-state acquisition (FIESTA) sequence revealed the tumor also extended into the right internal acoustic canal [Figure 1e]. The mass displayed intermediate diffusion signal when compared to adjacent CSF [Figure 1f]. There was a faint enhancement around the tentorium but no significant enhancement within the tumor [Figure 1g]. Computed tomography angiography revealed displacement of the basilar artery and the posterior cerebral arteries [Figure 1h].
Intraoperative pictures and postoperative imaging after tumor resection. (a and b) intraoperative pictures demonstrating a grayish pink tumor of moderate vascularization anteromedial to cranial nerves VII, VIII, XI, and X. The cranial nerves IV and VI were embedded within the tumor and preserved. CN, cranial nerves. Axial (c) and coronal (d) non contrast postoperative CT images showing the posterior petrosal approach. Axial FIESTA (e) and coronal (f) T1-weighted with contrast postoperative MRI images showing the extent of tumor resection, a small portion of meningioma was left in Meckel's cave.
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F2
A postoperative CT scan is shown in [Figure 2].
(a) Hematoxylin and eosin (x4) stained fragments of tissue with the proliferation of bland ovoid to epithelioid cells, with pink cytoplasm and indistinct cell borders. The whorled appearance is better appreciated. Nuclei appear to have some size variability, but no significant atypia or anaplasia is identified. The cystic pattern and angiomatous changes are also evident (x40). (b) Vimentin: Immunohistochemical staining for Vimentin shows a strong, diffuse cytoplasmic staining pattern. (c) Cyclin-D1: Immunohistochemical staining for Cyclin-D1 shows a diffuse staining pattern. (d) Reticulin: Immunohistochemical staining for reticulin shows an epithelioid staining pattern. (e) GFAP: Immunohistochemical staining for GFAP shows a strong, diffuse cytoplasmic staining pattern. (f) KI-67: Immunohistochemical staining for GFAP shows scattered positive staining, corresponding to a low proliferation index estimated to be <2%.
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F3
The lobulated component contained meningothelial whorls [Figure 3]. The tumor stained for Vimentin, glial fibrillary astrocytic protein (GFAP), and Cyclin D1, with low Ki-67 (<2%), and with an epithelioid reticulin pattern [Figure 3].