Venous sinus involvement in meningiomas and its association with intracranial hypertension features.

Abstract

e14109 Background: Meningiomas involving dural venous sinuses may cause symptoms mimicking idiopathic intracranial hypertension (IIH) through direct mass effect or raised intracranial pressure from impaired venous outflow. Optimal management must address both the tumor and potential venous obstruction. We sought to characterize this subset and identify factors guiding treatment selection. Methods: We retrospectively reviewed 63 meningioma patients at our institution. Cases were classified by venous sinus involvement based on invasion via imaging, compression, or occlusion of the superior sagittal sinus (SSS) or transverse-sigmoid sinus (TSS). We evaluated demographics, tumor size, WHO grade, symptoms, IIH features, treatment modality, and clinical outcomes. Results: Eleven patients (17.5%) had venous sinus involvement. Patients were predominantly female (81.8%) with mean age 51.9 ± 14.8 years. SSS involvement was most common (81.8%), followed by TSS (36.4%), with 27.3% affecting both systems. Venous sinus meningiomas were nearly twice as large as non-venous cases (2.87 vs 1.49 cm, p=0.08). Among graded tumors, 40% were WHO Grade 2-3, including one WHO Grade 3 malignant meningioma. Sinus invasion was present in 36.4%, compression in 18.2%, and occlusion in 36.4%. Importantly, 45.5% demonstrated IIH features. Four patients presented with papilledema, which was exclusive to venous-involved cases. Two patients had elevated venous pressures with SSS measurements of 27-39 mmHg and trans-stenotic gradients of 13-18 mmHg. Visual symptoms were the most common presentation (36.4%), followed by headaches (18.2%) and focal neurological deficits (18.2%). Treatment included surgical resection (36.4%), radiosurgery (9.1%), conservative monitoring (18.2%), IIH-directed therapy (18.2%), and venous stenting (9.1%). Headache resolution occurred in 60% of surgical patients. One patient treated with venous stenting achieved sustained migraine control. Two conservatively managed patients remained stable at 7-year follow-up, and no mortality was observed. Conclusions: Venous sinus meningiomas are a distinct clinical entity with larger tumor size, higher-grade histology, and IIH features in 45.5% of patients. This data supports the extrinsic venous compression hypothesis for IIH, and that venous stenting may provide symptom relief in select patients with predominant IIH features and preserved sinus patency. For clinical practice, we recommend: (1) fundoscopic examination in all meningioma patients with sinus-adjacent tumors to evaluate for papilledema; (2) diagnostic cerebral venography with pressure measurements when trans-stenotic gradients may influence treatment; (3) shorter surveillance intervals (6 months vs. 12) for conservatively managed patients given the 40% high-grade rate; and (4) evaluation incorporating both tumor resection and venous recanalization options.