Endocrine Abstracts

Introduction: Giant pituitary adenomas (GPAs) are traditionally defined as the tumors with the greatest diameter at or above 40 mm. However, some clinical series of GPAs include tumors with maximal diameter of 35 to 40 mm, and those tumors can be named ‘nearly giant’ pituitary adenomas (nearly GPAs). The treatment of GPAs is challenging and has a higher risk of complications due to the size and complex anatomical relations. This study was conducted to compare GPAs and nearly GPAs treated in The Maria Sklodowska-Curie National Research Institute of Oncology.

Material and methods: The study is a retrospective analysis of case series of GPAs and nearly GPAs treated with an endoscopic transsphenoidal approach in The Maria Sklodowska-Curie National Research Institute of Oncology from 2007 to 2023. The first study group included 176 patients with GPAs (66 women, 110 men), and the second group comprised 32 patients with nearly GPAs (6 women, 26 men). The mean age of patients at the time of surgery and observation time in the first group were 57.0 and 7.5 years, respectively, and in the second group 54.9 and 6.7 years.

Results: Patients with nearly GPAs had total resections more frequently (75.0%) compared to patients with GPAs (42.0%). The most common histopathologic diagnosis was the gonadotroph adenoma in both groups. GPAs more commonly showed invasion of the adjacent structures (73.3%) than nearly GPAs (46.9%). The treatment of GPAs was more often associated with complications. Moreover, patients with GPAs experienced serious complications (hematoma, hydrocephalus, coma, death), which were not observed in the nearly GPAs group.

Conclusion: GPAs differ significantly from nearly GPAs in clinical and morphological aspects. The diagnosis of a pituitary adenoma with a maximum diameter above 40 mm is associated with a poorer prognosis and should prompt a more intense treatment.