Clinical presentation and surgical outcomes of very large and giant pituitary adenomas: 80 cases in a cohort study of 306 patients with pituitary adenomas.

Purpose: To identify differences in the presentation and surgical outcomes between very large (30-39 mm) and giant (≥ 40 mm) (LARGE group) pituitary adenomas (PAs) compared to the smaller group (< 30 mm) (non-LARGE group).

Methods: Eighty patients with very large (n = 44) or giant (n = 36) PAs and 226 patients in the non-LARGE group who underwent tumor resection by pituitary surgery between 2008 and 2023 were studied. Hormonal, radiological, ophthalmological, and pathological data, and surgical outcomes were evaluated.

Results: Preoperatively, patients of the LARGE group presented more frequently with visual impairment (82.5% vs. 22.1%, P < 0.001) and with pituitary apoplexy (15.0% vs. 2.7%, P < 0.001) than the non-LARGE group. Moreover, the LARGE group were more commonly associated with preoperative panhypopituitarism (28.8% vs. 6.2%, P < 0.001). This group presented cavernous sinus invasion more frequently (71.3% vs. 23.9%, P < 0.001). The non-LARGE group achieved surgical cure more often than the LARGE group (79.7% vs. 50.0%, P < 0.001), and the rate of major complications was higher in the latest (8.8% vs. 1.3%, P < 0.004).

Conclusions: PAs ≥ 30 mm are most frequently accompanied by hormonal dysfunction, cavernous sinus invasion, and visual impairment. All this implies lower resection rates and higher postoperative complications than the smaller adenomas, posing a real surgical challenge.