PMC9062893_01
Preoperative imaging of the patient. MRI revealed a right CPA tumor suspected to be a vestibular schwannoma (a), a right sphenoid ridge extra-axial tumor suspected to be meningioma (b), and a left temporal extra-axial tumor also suspected to be a meningioma (b, arrow head). MRI: magnetic resonance imaging, CPA: cerebellopontine angle.
SNI-13-143-g001.jpg
PMC9062893_01_SNI-13-143-g001.jpg
F1
MRI revealed a right cerebellopontine angle (CPA) tumor suspected to be a vestibular schwannoma, a right sphenoid ridge extra-axial tumor suspected as meningioma, and a left temporal extra-axial tumor also suspected to be a meningioma [Figures 1a and 1b].
Imaging follow-up of the right CPA tumor. The right CPA tumor grew rapidly, with its maximum diameter expanding from 23 mm (a) to 35 mm (b) in 6 months, and the brainstem compression worsened. MRI also showed a marked increase in the size of the cyst. MRI: magnetic resonance imaging, CPA: cerebellopontine angle. To avoid persistent facial nerve palsy, we left a tiny tumor on the facial nerve while performing near total resection (resection rate: 99%) (c). Five months postoperatively, the right residual vestibular schwannoma in the internal auditory meatus had grown, so stereotactic radio surgery was performed for the recurrent lesion (d, arrow).
SNI-13-143-g002.jpg
PMC9062893_01_SNI-13-143-g002.jpg
F2
Magnetic resonance imaging (MRI) showed a marked increase in the size of the cyst [Figures 2a and 2b]. To avoid persistent facial nerve palsy, we left a tiny tumor on the facial nerve while performing near-total resection (resection rate: 99%; [Figure 2c]). Five months after surgery, the right residual lesion in the internal auditory meatus had grown, so stereotactic radiosurgery using Gamma Knife Icon (Elekta AB, Stockholm, Sweden) was performed for the recurrent lesion [Figure 2d].
Intraoperative images of tumor resection. The tumor extended into the internal auditory meatus, the cochlear nerve was running on the caudal side of the tumor, and the facial nerve was located on its ventral side, which was confirmed by electrophysiological monitoring (a). The tumor was soft and had a cystic component (b).
SNI-13-143-g003.jpg
PMC9062893_01_SNI-13-143-g003.jpg
F3
Intraoperative images of tumor resection are shown in [Figures 3a-b].
Histopathological findings of the tumor. Atypical Schwann cells with nuclear pleomorphism were observed, but mitotic figures were rarely seen (a). Degenerative changes such as hyalinized blood vessels, hemorrhage with hemosiderin deposition, lymphocytic infiltration, and cyst formation (b) were observed. Immunostaining showed diffuse S100 positivity (c) and the Ki-67 proliferation index was up to 5% (d). The diagnosis was ancient schwannoma (WHO Grade I). WHO: World Health Organization.
SNI-13-143-g004.jpg
PMC9062893_01_SNI-13-143-g004.jpg
F4
Immunostaining showed diffuse S100 positivity and the Ki-67 proliferation index was up to 5% [Figures 4ad].
Detailed timeline on the treatment and the time course. The upper row describes the detailed course of the treatment and the lower row describes the detailed clinical time course.
SNI-13-143-g005.jpg
PMC9062893_01_SNI-13-143-g005.jpg
F5