PMC8769444_01
Presurgical characteristics and location of a giant pituitary adenoma in a 41-year-old patient. (A) Preoperative CT showing a solid tumor filling the third ventricle. (B) The tumor is hyperintense on a T2WI, and the wall of the septum pellucidum in front of the fornix is bilaterally stretched (arrowheads). (C) In the sagittal image, the space between the anterior commissure (white arrow) and the fornix (black arrow) is expanded, and the foramen of Monro is shifted to the back due to compression by the tumor. (D) In the coronal image on Gd-T1WI, the tumor extends to the right cavernous sinus, and the right ICA is shifted (white arrow). (E) Arterial phase of the left internal carotid angiography shows many small arteries feeding the tumor. (F) Venous phase of the angiography reveals the tumor stain. CT: computed tomography, T2WI: T2-weighted MR image, Gd-T1WI: gadolinium-enhanced T1-weighted MRI, ICA: internal carotid artery.
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F1
No calcification or hemorrhage was observed (Fig. 1A). T2-weighted MR images (T2WIs) (Fig. 1B, C), stretching the wall of the septum pellucidum bilaterally in front of the column of fornix (Fig. 1B). The space between the anterior commissure and the fornix was expanded. The foramen of Monro was shifted backward by the tumor (Fig. 1C). The right internal carotid artery (ICA) was compressed and shifted by the tumor in the right cavernous sinus as seen on a coronal plane image by Gd-T1WI (Fig. 1D). Cerebral angiography showed feeders from the bilateral ICAs (Fig. 1E and 1F).
Intra-operative microscopic view and schema of the transventricular preforniceal approach. (A) The tumor is exposed into the right preforniceal space; the arrow, the solid arrowhead, and the open arrowhead show the tumor, the right column of fornix, and the foramen of Monro, respectively. (B) The schema of intraoperative microscopic view in the right ventricle. Contralateral anatomical structures have been demonstrated with transparent illustration. The wall of septum pellucidum was incised in front of the right column of the fornix, and the tumor was exposed in the back. (C) Tumor resection boundary for the endoscopic transsphenoidal approach. The endoscopic tool (arrowhead) is observed in a microscopic view. (D) Cerebral aqueduct (arrowhead) is revealed after the tumor removal. ASV: anterior septal vein, CF: column of fornix, CP: choroid plexus, FM: foramen of Monro, TSV: thalamostriate vein.
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F2
The foramen of Monro and the column of the fornix were identified, and a preforniceal incision was made to enter the septum pellucidum (Fig. 2A and 2B). Tumor resection was continued to reach the sellae diaphragm, also achievable by ETSS (Fig. 2C). The cerebral aqueduct was observed after tumor removal (Fig. 2D).
Postoperative residual tumor characteristics in the 41-year-old patient. (A) Postoperative Gd-T1WI showing the small residual tumor (arrowhead) in the right cavernous sinus and (B and C): behind the AComA; most of the tumor was removed sufficiently. (D) Diffusion-weighted image showing a high-intensity signal around the right midbrain cerebral peduncle, but damage in other brain areas is not observed. Gd-T1WI: gadolinium-enhanced T1-weighted MRI, AComA: anterior communicating artery.
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F3
Postoperative MRI showed that most of the tumor (approximately 94% of the volume) had been removed, except for the residual tumor in the right cavernous sinus and behind the AComA (Fig. 3A-3C). Hyperintense spots on diffusion-weighted images were seen in the right cerebral peduncle (Fig. 3D), corresponding to slight motor weakness in the left cerebral peduncle, which resolved in a week.