PMC9479550_01
Preoperative magnetic resonance imaging. Axial T2-weighted (a) and T1-weighted images with gadolinium enhancement (b) images show that the tumor is isointense with cystic components and is enhanced mainly in the peripheral area. The tumor is mainly in the clivus, and the small part of the tumor protrudes toward the brainstem around the left hypoglossal canal (the left hypoglossal canal: b,c, and e, white arrow). Axial (c and d) and coronal (e) bone window computed tomography images show destruction of the hypoglossal canal and jugular foramen (d and e, white dot arrow). The clival bone itself is expanded due to the tumor invasion (c and d), and the bony cortex is preserved in most parts (d, arrowhead).
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F1
T2-weighted images and heterogeneous enhancement mainly in the peripheral area with gadolinium (Gd) on T1-weighted images [Figures 1a and b]. The tumor was mainly located in the clivus and it extended down to the left jugular tubercle and occipital condyle, partially protruding toward the medulla oblongata from the hypoglossal canal [Figure 1b]. A computed tomography (CT) scan revealed an osteolytic lesion that destructed the hypoglossal canal and expanded the clivus while preserving the bony cortex [Figures 1c-e].
Intraoperative findings of transmaxillary-pterygoid approach combined with translacerum approach. (a) Intraoperative endoscopic view showing the area around the left internal carotid artery (ICA) at the foramen lacerum. (b) The cancellous bone of the clivus is replaced by the grey-yellowish tumor. (c) Cranial nerve IX, X, or XI (white arrow) is seen at the rostral margin of the tumor around the jugular foramen.
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F2
The bone overlying the left paraclival carotid artery was removed, and the fibrocartilaginous tissue attached to the internal carotid artery (ICA) and Eustachian tube around the foramen lacerum was disconnected to enable mobility of these structures [Figure 2a]. The cortical bone in the clivus was thinned, and the cancellous bone was replaced by the tumor [Figure 2b]. The left cranial nerve IX, X, or XI was observed at the rostral margin of the tumor around the jugular foramen during tumor removal [Figure 2c].
Postoperative magnetic resonance imaging. (a and b) Axial and sagittal T1-weighted imaging with gadolinium enhancement shows subtotal resection of the tumor. The residual tumor is found behind the internal carotid artery lateral to the left occipital condyle (white arrow).
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F3
Postoperative MRI showed subtotal resection of the tumor with successful decompression of the brain stem with a small residual tumor lateral to the occipital condyle [Figures 3a and b].