PMC9650989_01
Visual field tests before and after surgery. (A, B) Preoperative ophthalmologic examinations indicating bilateral tunnel visual fields. (C, D) Postoperative visual field tests three months after surgery showing slight peripheral visual field loss in bilateral eyes. OD, oculus dexter; OS, oculus sinister.
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Ophthalmological examination identified visual acuity in the right eye of 0.12 and in the left eye of 0.4, with bilateral tubular visual fields ( Figures 1A, B ). The timeline of the overall therapeutic process is shown as a flow diagram in  Supplemental Figure 1 . Ophthalmological examination showed her visual acuity improved to 0.8 in the left eye and 0.5 in the right eye, and bilateral vision fields has almost returned to normal except for slight peripheral defects ( Figures 1C, D ).
Radiological evaluation of the suprasellar lesion preoperatively. (A-F) Preoperative CT and MRI scans showing a typical retroinfundibular CP. This lesion manifested as a hypodense irregular mass with calcification located in the suprasellar lesion (A), which was hypo-intense on T1WI (B) and hyper-intense on T2WI (C). Post-contrast (gadolinium-enhanced) axial (D), sagittal (E), and coronal (F) MRI showed a thick, irregular enhancement of the solid part and a slight rim enhancement of the cystic component. (G-I) Preoperative axial (G), sagittal (H), and coronal (I) CT angiography images showed the relative location of the tumor to the Willis' circle. Note that in this patient the basilar apex was at a higher position surpassing the posterior clinoid process. The yellow arrows denote posterior clinoid process, while the red arrows depict the basilar apex.
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Computed tomography (CT) and magnetic resonance (MR) imaging revealed a well-circumscribed, multilobular, suprasellar mass containing solid and cystic components with calcification ( Figures 2A-D ). This lesion was found to occupy the retro-infundibular space and extend inferiorly in front of the brainstem and upward into the TV, displacing the midbrain posteriorly and the optic chiasm anteriorly ( Figure 2E ). Gadolinium-enhanced MR imaging demonstrated a thick, irregular enhancement of the solid part and a slight rim enhancement of the cystic component ( Figures 2D-F ). The pituitary stalk was clearly shown in the midline on the coronal section ( Figure 2E ). CT angiography (CTA) revealed the existence of right fetal posterior communicating artery (PComA) ( Figure 2G ) as well as the relative location of the tumor to the Willis' circle ( Figures 2G-I ). H&E staining, the squamous cell epithelium of the tumor was not easily recognizable ( Figures 4A, B ). However, in subsequent immunohistochemical investigations, the morphological characteristics of this type of epithelium were evident, particularly in the CK 5/6 staining ( Supplemental Figure 2 ). Figure 2 ). Further molecular pathologic analyses showed that the tumor exhibited BRAF (V600E) mutations instead of CTNNB1 mutations.
Surgical procedure and nuances of the EF-SCITA approach. (A) The lateral prone position for a right-sided EF-SCITA approach. (B) Head position and surface landmarks for the transverse/sigmoid, the curved skin incision (red line), the proposed bone window (yellow rounded rectangle), the mark for drilling sites including the asterion and another site located 3.5 cm medial to the asterion (black circles), and the Y-shaped durotomy (red dotted lines). (C) Endoscopic explorations in the lateral supracerebellar infratentorial space. (D) The incision of the tenrorium for exposure of the crural cistern. The yellow arrowheads denote the edge of the cut tentorium. (E) The exposure of the posterior capsule of the cystic lesion in the supra-oculomotor space. (F) The exposure of the solid part of the tumor in the supra-oculomotor space after aspiration of the contents. (G, H) Dissection of the solid tumor from the pituitary stalk in the infra-oculomotor space. The anatomical boundaries of the supra-oculomotor and infra-oculomotor spaces are clearly seen. The blue arrowheads indicate bilateral posterior clinoid processes. (I) The endoscopic view of subtotal removal of the tumor, with a small part of the solid lesion adhering to the pituitary stalk left. BA, basilar artery; Cer, cerebellum; CN II, optic nerve; CN III, oculomotor nerve; CN IV, trochlear nerve; ICA, internal carotid artery; PCA, posterior cerebral artery; PCoA, posterior communicating artery; Ped., pedunculus cerebri; PS, pituitary stalk; SCA, superior cerebellar artery; SPV, superior petrosal vein; T, tumor. Temp., temporal lobe; Tent., tentorium.
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The head was fixed with a Mayfield clamp and placed in upper flexion of 30  to allow gravity retraction of the cerebellum ( Figures 3A, B ). A Y-shaped duratomy was then made, with the superior part of the dural flap turned over to the margin of the transverse sinus ( Figure 3B ). Gravity retraction, together with intraoperative cerebrospinal fluid draining (approximately 40 ml) with the aid of a preoperatively inserted lumbar drainage tube, expanded the infratentorial space allowing endoscopic explorations in the lateral superior cerebellar space and exposure of the superior petrosal vein (SPV), trochlear nerve (CN IV), and tentorium ( Figure 3C ). A 1-cm incision was made in the anterior part of the tentorium for exposing the crural cistern ( Figure 3D ), with much attention paid to the CN IV during the procedure. Under direct view, the crural cistern was separated into two spaces by the CN III: the supra-oculomotor triangle formed by the midbrain, temporal lobe, and CN III, as well as the infra-oculomotor triangle formed by the cerebral peduncle, dorsum sellae, and CN III ( Figures 3E-G ). After dissection of the supra-oculomotor space, the posterior portion of the cystic lesion was revealed ( Figure 3E ) and "motor-oil"-colored fluid could be drained from the cyst. After opening the capsule, the solid lesion in front of the pituitary stalk (PS) could be easily identified in the suprasellar cistern, together with right internal carotid artery (ICA) as well as the displaced optic nerve ( Figure 3F ). The basilar artery could also be observed in the infra-oculomotor space when uplifting the CN III and PCoA ( Figure 3G ). Figures 3G-I ). Finally, the capsule was bluntly removed from the surrounding reactive gliotic layer.
Pathological and radiological evaluation of the lesion postoperatively. (A, B) Photomicrographs of hematoxylin-eosin staining showing typical features of papillary craniopharyngioma. The framed area in (A) was magnified in (B). Bars = 200 mum in (A) and 40 mum in (B). (C-F) Postoperative CT (C) performed immediately after surgery and post-contrast sagittal (D), coronal (E), and axial (F) MRI scans performed three months after surgery showing subtotal removal of the lesion, with a few calcified components left in the suprasellar region.
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H&E staining, the squamous cell epithelium of the tumor was not easily recognizable ( Figures 4A, B ). However, in subsequent immunohistochemical investigations, the morphological characteristics of this type of epithelium were evident, particularly in the CK 5/6 staining ( Supplemental Figure 2 ). The underlying stroma was edematous and fibrotic with several congested vascular channels ( Figures 4A, B ). Postoperative imaging examinations demonstrated STR of the tumor ( Figures 4C-F ).