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

Comparison of Surgical Modalities for Giant Pituitary Adenoma: A Systematic Review and Meta-Analysis of 1413 Patients

BACKGROUND AND OBJECTIVES

Giant pituitary adenomas (GPAs) are a challenging clinical entity, composing 5% to 15% of all pituitary adenomas. While the endoscopic endonasal transsphenoidal (EET) approach has surpassed the microsurgical transsphenoidal (MT) and transcranial (TC) approaches as the first-line surgical modality in most institutions, a systematic review comparing the 3 approaches has not been undertaken since 2012. Given growing adoption of EET and development of novel operative techniques over the past decade, an updated comparison of GPA surgical modalities is warranted.

METHODS

We identified all studies related to the surgical management of GPAs in PubMed, Embase, and Web of Science from inception to December 31, 2021. End points assessed included gross total resection (GTR) rates, postoperative visual improvement, mortality, and perioperative complications.

RESULTS

After screening of 1701 studies, we identified 45 studies on the surgical management of GPAs for meta-analysis. Thirty-one used the EET approach (n = 1413), 11 studies used the MT approach (n = 601), and 10 used the TC approach (n = 416). The cumulative number of patients treated by EET did not exceed that of patients treated by the TC or MT approaches until 2014 and 2015, respectively. Despite patients undergoing EET having the highest average tumor diameter, pooled rates for GTR were significantly higher for EET (42%) than MT (33%, P < .001) and TC (8%, P < .001) and EET similarly exhibited superior rates of visual improvement (85%) than MT (73%, P < .001) and TC (56%, P < .001). Mortality rates were comparable between EET (0.6%) and MT (1.6%), but EET had significantly lower mortality than TC (2.7%, P < .001). Compared with MT, EET had lower rates of hypopituitarism (8.5% vs 14.9%, P = .012) but higher rates of diabetes insipidus (3.1% vs 0.5%, P = .001).

CONCLUSION

In an updated meta-analysis of 1413 patients with GPA, EET resection conferred significantly higher rates of visual improvement and GTR, when compared with the MT and TC approaches.

Giant Clinically Non-Functioning Pituitary Adenoma Presenting as New Onset Generalized Tonic‒Clonic Seizures: A Case Report

Background

Giant Clinically Non-Functioning Pituitary Adenomas (GCNFPA) are pituitary neuroendocrine tumours spanning beyond 4 cm in diameter without clinically apparent secretory function. They elicit insidious growth pertaining to its asymptomatic nature and present at large sizes from mass effect. Certain clinical features such as headache and visual disturbances are common presentations of GCNFPAs owing to their size, while others such as seizures are extremely rare.

Case Report

A 63-year-old woman presented with back-to-back generalized tonic clonic seizures to the A&E and was treated with Levetiracetam. Following initial normal blood investigations, a visual field analysis revealed a bitemporal upper quadrantanopia and further evaluation using MRI found a giant pituitary lesion with suprasellar extension through the third ventricle into the lateral ventricles with significant mass effect. She underwent neuro-navigation guided endonasal transsphenoidal subtotal resection 2 weeks later. The histological diagnosis of null cell adenoma with a Ki67 of 3% was made. At 3 months of follow-up, she is symptom free and monitored with serial MRIs.

Conclusion

Seizures are an uncommon presentation of GCNFPAs limited to a few case reports. This illustrates the importance of careful evaluation of patient presentations to correctly diagnose pituitary neoplasms and prioritizing symptom relief in choosing surgical approaches.

Large Pituitary Adenoma: Strategies to Maximize Volumetric Resection Using Endoscopic Endonasal Approaches and an Analysis of Factors Limiting Resection

BACKGROUND

Large pituitary adenomas (LPAs), which constitute ∼5%-14% of all pituitary adenomas, are considered challenging tumors owing to their locally aggressive behavior, low gross total resection rate, and high prevalence of visual deficits and hypopituitarism. We evaluated the utility of various extended endoscopic endonasal approaches in maximizing the resection of LPAs and studied the factors affecting the extent of surgical resection.

METHODS

A retrospective study of all LPAs (defined as a minimum diameter >3 cm and tumor volume >10 cm3) treated via an endoscopic endonasal approach between January 2015 and December 2020 was performed. The volumetric extent of resection (3-dimensional volumetric analysis software) was correlated with various demographic, tumor-related, pathologic, and immunohistochemical factors and its effects on the clinical outcomes studied.

RESULTS

The present study included 106 patients with LPAs. The mean extent of the resection volume was 79.18 ± 21.75 cm3. The factors that affected the extent of resection included the preoperative tumor volume (P = 0.03) and Knosp grade (P = 0.03). The percentage increase in the extent of resection with the use of 2 endonasal corridors was 10.6% and with 3 corridors was 14%. Visual improvement occurred in 82% of patients, and new-onset persistent hormonal insufficiency occurred in 2.9% of patients. Mortality directly related to surgery occurred in 1.8% of cases.

CONCLUSIONS

Extended endoscopic endonasal approaches can safely and effectively be used for gross total resection of LPAs. However, we found that the preoperative tumor volume and Knosp grade were significant factors affecting the extent of tumor resection. The use of multiple endoscopic endonasal corridors can increase the volumetric extent of resection for LPAs.