Endoscopic Endonasal Approach for Giant Pituitary Adenoma Occupying the Entire Third Ventricle: Surgical Results and a Review of the Literature.

Background: Pituitary macroadenomas occasionally disrupt the sellae diaphragma and extend directly to the third ventricle causing hydrocephalus. We present the results of a single-stage extended endoscopic approach for managing giant pituitary adenomas (GPAs) occupying the entire third ventricle.
Methods: A retrospective study of all GPAs occupying the entire third ventricle operated on via the endoscopic endonasal approach between January 2016 and December 2020 was performed.
Results: The study included 8 cases of GPA occupying the entire third ventricle, of which 2 (25%) were functioning adenomas. Of 8 patients, 4 (50%) presented with hydrocephalus, 2 underwent preoperative ventriculoperitoneal shunt, and 2 had an intraoperative external ventricular drain. No patients had postoperative cerebrospinal fluid rhinorrhea. Complete resection of the third ventricular component could be achieved in all cases radiologically; minimal residual tumor was present either in the lateral compartment of the cavernous sinus or over the anterior cerebral artery complex in 5 of 8 (62.5%) patients. Complete resolution of temporal hemianopia was seen in 8 of the 12 eyes (66.67%), and partial resolution was seen in 4 of 12 (33.3%) eyes. At a mean follow-up of 24.62 ± 10.01 months, none of the patients needed another surgical procedure.
Conclusions: The extended endonasal endoscopic approach can be safely and efficiently used for single-stage excision of GPAs that disrupt the diaphragm and occupy the third ventricle. Preoperative cerebrospinal fluid diversion may be used to manage associated acute hydrocephalus in these cases.
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