Silent Corticotroph Adenomas Demonstrate Predilection for Sphenoid Sinus, Cavernous Sinus, and Clival Invasion Compared with Other Subtypes

Background: Nonfunctional pituitary neuroendocrine tumors (PitNETs) exhibit wide variability in growth pattern based on subtype. Silent corticotroph adenomas (SCAs) demonstrate aggressive growth compared with other nonfunctional pituitary adenomas (NFPAs), especially into the cavernous sinus. In this study, we sought to characterize other growth patterns of SCAs compared with NFPAs.

Methods: We performed a retrospective analysis of all patients with nonfunctional PitNETs treated with surgical resection via endoscopic endonasal approach at a single institution from August 1, 2018, to May 11, 2024. Preoperative computed tomography and magnetic resonance imaging were reviewed to determine extension into the suprasellar space, sphenoid sinus, cavernous sinus, and clivus.

Results: The study comprised 91 patients, including 20 SCAs and 71 NFPAs. SCAs demonstrated significantly greater rates of growth into the sphenoid sinus (55.0% vs. 23.94%, P = 0.013), clivus (65.0% vs. 16.9%, P < 0.0001), and cavernous sinus (defined as Knosp grade 3 or 4; 55.0% vs. 23.35%, P = 0.016). Other NFPAs were more likely to grow into the suprasellar space (92.96% vs. 75.0%, P = 0.038). Tumor volume was similar between groups (11.93 cm³ vs. 9.06 cm³, P = 0.2).

Conclusions: Silent corticotroph PitNETs demonstrate predilection for invasion of bony structures, with higher rates of growing through the sellar floor into the sphenoid sinus, growing posteroinferiorly into the clivus and laterally into the cavernous sinuses. Other nonfunctional PitNETs tended to follow the path of least resistance, growing superiorly into the suprasellar space. These differences in growth patterns may account for some of the clinical challenges of treating silent corticotroph PitNETs.