2025 Proffered Presentations
S002: PATTERNS OF INVASION OF PITUITARY ADENOMAS INTO THE MEDIAL WALL AND CAVERNOUS SINUS COMPARTMENTS
Felipe Constanzo, MD1; Jonathan Rychen, MD2; Thomas Johnstone2; Christine K Lee, MD, PhD2; Vladimir Ljubimov, MD2; Yuanzhi Xu, MD2; Vera Vigo, MD2; Alix Bex, MD2; Enrico Gambatesa, MD2; Juan Carlos Fernandez Miranda, MD2; 1Clinica Bio Bio; 2Stanford University
Objective: Cavernous sinus (CS) invasion is considered one of the most important factors for extent of resection of pituitary adenomas. Resection of the medial wall of the cavernous sinus (MWCS) and CS exploration has been increasingly used by experienced pituitary surgeons. By standardizing this technique, we noticed that pituitary adenomas have different patterns of lateral extension, which we set out to describe.
Materials and Methods: Based on intraoperative observation of 159 CS explorations, we classified MWCS invasion in 3 groups: focal invasion (microscopic/nodular attachment to the wall), wall thickening (adenoma growing within the MWCS), and wall destruction (adenoma piercing through the wall). General demographics; previous surgery; apoplexy; size (micro vs macroadenoma); hormonal status; transcription factors; tumor consistency (soft vs fibrous), invasion into each CS compartment, invasion of the carotid-clinoid ligament, degree of carotid adherence (not significantly adhered vs significantly adhered); extent of resection (EOR); and anatomic complications (cranial nerve [CN] palsy, cerebrospinal [CSF] leak, ICA injury/stroke, and haematoma) were compared between those groups.
Results: The most frequent pattern of invasion was medial wall destruction (47.2%), followed by wall thickening (28.9%) and focal invasion (23.9%). Functional adenomas comprised most of the cases focally invading the wall (92.1%), and thickening the wall (82.6%), but only half of those causing wall destruction. Wall thickening was associated with a significantly high prevalence of microadenomas (32.6%), recurrences (45.7%), fibrous consistency (45.7%), ligament invasion (43.5%), and carotid adherence (60.9%). All cases with focal invasion of the MWCS extended into the CS, whereas 59% of wall thickening and 100% of wall destruction had intracavernous tumor (p<0.0001). Adenomas causing wall destruction had twice the number of invaded compartments than wall thickening (2.5% vs 1.2%), while adenomas causing focal invasion did not invade CS compartments (p<0.0001). Macroadenomas were more likely to invade into the CS (71.5% vs 45%, p<0.0001), as were non-functioning adenomas (88.5% vs 52.3%, p<0.0001). Gross total resection (GTR) of the intracavernous tumour was achieved in 87.4% of cases. GTR was more frequently achieved in microadenomas (100% vs 77%, p 0.024); and in wall thickening, when compared to wall destruction (97.8% vs 74.7%, p<0.0001). Complications occurred in 20 patients (13.9%), with 5 postoperative CSF leaks, 11 transient CN palsies, and 3 postoperative haematomas. Complications only occurred in cases with CS compartment invasion. Only two cases of postoperative CSF leaks were directly associated with transcavernous resection (breach in the oculomotor triangle). The rate of transient CN III palsy was 3.9% for tumours in the superior compartment, and 12% for lateral compartment. For CN VI palsy, the rates were 10.4% for inferior compartment, 8% for lateral compartment, and 11.3% for posterior compartment.
Conclusion: Pituitary adenomas may invade the wall focally, grow within the wall, or destroy the medial wall of the cavernous sinus, with each pattern conveying a particular surgical challenge.
Figure 1: Focal Invasion
Figure 2: Thickening of the medial wall of the cavernous sinus
Figure 3: Destruction of the medial wall of the cavernous sinus.