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

Purpose: To identify differences in the presentation and surgical outcomes between very large (30–39 mm) and giant (≥40mm) (LARGE group) pituitary adenomas (PAs) compared to the smaller group (< 30mm) (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 apoplexy (15.0% vs. 2.7%, P < 0.001) than the non-LARGE group. Moreover, the LARGE group is 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 small adenomas, posing a real surgical challenge.