Spheno-orbital Meningiomas: Does the Residual Hyperostosis Have an Impact on the Risk of Recurrence?

Background: Meningiomas arising on the lesser and greater sphenoid wings represent approximately 18% of total cases. Only 2-9% of these are properly defined as spheno-orbital meningiomas (SOM). SOM are characterized by the pathognomonic hyperostosis of the sphenoid bone, whose mechanism is still debated. Clinical presentation with proptosis, visual impairment, diplopia, and headaches is related to the proximity with critical structures within the orbit, optic nerve canal, superior orbital fissure, and cavernous sinus. As a result, gross-total resection is possible only in limited cases. Notably, the relation between the extent of resection and risk of recurrence is still undefined, especially for the bony tumor portion (BTP).

Objective: To identify potential correlations between the recurrence rate of SOM and the extent of resection of the bony (BTP) and soft tumor portions (STP) and to analyze the progression-free survival of patients harboring SOM in light of other known risk factors such as demographic, clinical, and radiological features. To the best of our knowledge, this is the largest case series of SOM ever described.

Methods: This retrospective study included patients who underwent surgical resection of a SOM between 2011-2021 at our Institution. Demographic and clinical data was retrieved from the institutional medical record and using a questionnaire administered through phone calls. Pre- and post-operative brain CT and MRI scans were analyzed. Based on the radiological appearance, STP and BTP were identified, and their volumes segmented. Progression-free survival was presented with the Kaplan–Meier method considering the possible treatments at recurrence (stereotactic radiosurgery (SRS) versus surgery) and the Youden index for the STP residual cut-off.

Results: The study cohort included 89 patients diagnosed with SOM (8.9/1–F/M). 60.1% of patients had a history of contraceptive assumption for more than 10 years. There was no significant correlation between the postoperative BTP volume and the recurrence rate (p > 0.05) whereas a significant correlation was identified for the STP (<0.001 – aOR 1.342). The percentage of patients who recurred after first surgery was 22,4%. 35% of these patients underwent surgery as a second treatment while 65% were treated with SRS. Only 3.37% of patients underwent three surgical treatments over the follow-up time. Patients who had a STP volume above 3.7 mm³ postoperatively had an adjusted odds ratio of 1.342 for risk of recurrence. The mean follow-up time was 6.5 years (± 2.9).

Fig. 1 Box-plot showing the statistically significant difference in the rate of recurrence in relation to the postoperative STP.

Fig. 2 Box-plot showing the absence of a statistically significant difference in the rate of recurrence in relation to the postoperative BTP.

Fig. 2 AROC curve showing high specificity and sensitivity of STP as an index of risk of recurrence.

Conclusions: This study suggests that the extent of resection of STP may reduce the recurrence rate of SOM, while this may not be the case for the BTP. The surgical strategy for SOM should be patient-based with the aim of achieving safe maximal resection of the STP. Conversely, the BTP removal should be guided by the need to decompress anatomical structures in order to preserve neurological functions.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
05 February 2024