case_images: PMC6581985_01
case_images: (A) A magnetic resonance image with gadolinium enhancement obtained at the initial visit shows an ovoid tumor with a maximum diameter of 8 cm on the left sphenoid ridge. The tumor was exerting strong pressure on the brain and was progressing further from the tip of the temporal bone (yellow arrow) into the sphenoid sinus (red arrow). (B) A magnetic resonance image with gadolinium enhancement obtained after a subtotal tumor excision by craniotomy. The temporal lobe tumor was removed but the tumor at the tip of the temporal bone to the sphenoid sinus remained. (C) A magnetic resonance image with gadolinium enhancement obtained 20 months after the subtotal tumor excision. The tumor remaining at the tip of the temporal bone to the sphenoid sinus was increasing in size. (D) A preoperative non-contrast-enhanced computed tomography image obtained before surgery via the endoscopic endonasal approach shows that the lateral recess of the sphenoid sinus was markedly enlarged and there was a soft tissue shadow occupying the left sphenoid sinus. Erosion was confirmed in the part of the bone bordering the lateral tip of the temporal lobe, suggesting a bone fracture in the order of several millimeters at this site (white arrow). (E) A magnetic resonance image with gadolinium enhancement obtained after surgery via the endoscopic endonasal approach confirming that the tumor within the sphenoid sinus had been completely removed, with residual tumor tissue remaining only at the tip of the left temporal lobe (yellow arrow). (F) A magnetic resonance image with gadolinium enhancement obtained after total resection of the residual tumor via craniotomy. No presence or recurrence of the tumor within the cranium or sphenoid sinus was observed.
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case_images: PMC6581985_01_gr1.jpg
case_images: fig0005
case_images: Neuroimaging studies revealed a left-sided sphenoid ridge meningioma; the tumor was exerting pressure on the brain parenchyma and extended further from the temporal lobe into the sphenoid sinus (Fig. 1A). Subtotal tumor excision via craniotomy was performed by the neurosurgeons, but the portion of the tumor extending anterior to the tip of the temporal bone to the sphenoid sinus was not removed (Fig. 1B). After 2 years of regular postoperative follow-up, the residual tumor was noted to have increased in size (Fig. 1C). Computed tomography revealed that the tumor had grown considerably in the lateral recess of the sphenoid sinus and that there was a soft tissue shadow occupying the left sphenoid sinus (Fig. 1D). Six months later, the neurosurgeons performed a craniotomy to remove the tumor from the area extending from just anterior to the tip of the temporal bone to the sphenoid sinus (Fig. 1E, F).
case_images: (A) Reconstruction of the nasal septum. The left septal mucosa was detached under the periosteum up to the vomer. (B, C) After the vomer and mucosa of the anterior wall of the sphenoid sinus were removed, part of the tumor was clearly visualized. (D) The left paranasal cavity was opened and a modified endoscopic medial maxillectomy was performed. (E) The sphenopalatine and descending pharyngeal arteries were clipped and severed. The communicating branch of the nerve was severed at this time. (F) Confirmation of V2 on bone of the posterior wall of the pterygopalatine fossa. (G, H) The left lateral recess of the sphenoid sinus was approached. Examination of the overall image of the tumor revealed that the base was in the lateral wall of the left sphenoid sinus. (I) The base of the tumor was subsequently severed using a nasal snare. (J, K) The body of the tumor was removed. (L) After removing the remaining tumor at the base using forceps, packing was performed and the surgery was completed.
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case_images: PMC6581985_01_gr2.jpg
case_images: fig0010
case_images: The septal mucosa was detached under the periosteum up to the vomer (Fig. 2A). After the vomer was removed using a drill, the mucosa of the anterior wall of the sphenoid sinus was removed, affording a clear view of one portion of the tumor (Fig. 2B). Next, the left paranasal cavity was opened and a modified endoscopic medial maxillectomy (EM3) was performed (Fig. 2C). After the posterior wall of the left maxillary sinus was skeletonized with a drill, the sphenopalatine and descending pharyngeal arteries were clipped and cut (Fig. 2D). After confirmation of the maxillary nerve (CN V2) at the bone on the posterior wall of the pterygopalatine fossa (Fig. 2E), the left lateral recess of the sphenoid sinus was approached (Fig. 2F, G). The base of the tumor was in the lateral wall of the left sphenoid sinus and penetrated from the area just anterior to the tip of the temporal bone to the sphenoid sinus via a pin-sized area of bone erosion, so the tumor was removed using a nasal snare (Fig. 2H). The body of the tumor was then removed (Fig. 2I).
case_images: (A) Hematoxylin-eosin staining at the initial craniotomy. The relatively uniform-type circular nucleus and spindle cells with abundant cytoplasm exhibited substantial hyperplasia. This was diagnosed as transitional (mixed) meningioma, World Health Organization grade I. (B) Hematoxylin-eosin staining at the time of the endoscopic endonasal approach. (C) Hematoxylin-eosin staining at the time of the second craniotomy showing nuclear enlargement and increased nuclear density. (D) Anti-Ki-67 antibody staining at the initial craniotomy. The MIB-1 index was 1% or less. (E) Anti-Ki-67 antibody staining at the time of the endoscopic endonasal approach. The MIB-1 index was approximately 5%. (F) Anti-Ki-67 antibody staining at the time of the second craniotomy. The MIB-1 index was approximately 15%. However, mitosis, among other processes, was limited, and there were no malignant findings.
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case_images: PMC6581985_01_gr3.jpg
case_images: fig0015
case_images: The pathological diagnosis was a World Health Organization grade I transitional meningioma (Fig. 3A). The MIB-1 index was less than 1% (Fig. 3D). The MIB-1 index of the sphenoidal portion was 5% with no difference in the pathology (Fig. 3B, E). Thereafter, the MIB-1 index increased to 15% with nuclear enlargement and increased nuclear density (Fig. 3C, F).