Successful management of an intraluminal superior sagittal sinus meningioma causing elevated intracranial pressure using gamma knife radiosurgery in subacute setting: A case report

Abstract

Background: Gamma Knife stereotactic radiosurgery (GKRS) facilitates precisely focused radiation to an intracranial target while minimizing substantial off-target radiation in the surrounding normal tissue. Meningiomas attached to or invading the superior sagittal sinus may result in sinus occlusion and are often impossible to completely resect safely. The authors describe successful management of a patient with a meningioma located completely inside the posterior aspect of the superior sagittal sinus.

Case description: A 46-year-old woman presented to the emergency department with progressive generalized headaches accompanied by worsening vision. The patient underwent a diagnostic brain magnetic resonance imaging which showed a solitary a 7 × 6 × 10 mm homogeneously contrast-enhancing lesion within the lumen of the posterior aspect of superior sagittal sinus without ventricular enlargement or peritumoral edema. The lesion was thought to be a meningioma radiographically. To evaluate the suspected increased intracranial pressure, a lumbar puncture was subsequently performed and demonstrated an opening pressure of 30 cm H2O. After drainage of 40 cc of CSF, the spinal closing pressure was 9 cm H2O. After failure of conservative management with acetazolamide, and determination of surgical inoperability due to the critical intraluminal location of the mass lesion, the patient underwent Gamma Knife radiosurgery. The 0.36 cc tumor was treated as an outpatient in the Perfexion® model Gamma Knife with a highly conformal and selective plan that enclosed the 3D geometry of the tumor with a minimal margin tumor dose of 14 gy at the 50% isodose. Three months after GKRS, the patient reported continued reduction in the frequency and severity of both her headaches and her visual disturbance. Ophthalmological consultation noted progressive resolution of her optic disc edema confirmed by formal optical coherence tomography. The patient is now 3 years out from GKRS with complete resolution of headache symptoms along with persistent reduction in tumor size (3 × 1 × 4 mm) on serial period imaging and resolution of papilledema.

Conclusion: Tumors located in such critical anatomic regions, as in our patient, should be considered for primary GKRS when the risks of biopsy or removal are too high. GKRS was able to provide great radiographic and clinical result in an intricately located meningioma.

Keywords: Gamma Knife radiosurgery; Image-guided neurosurgery; Lesion; Radiosurgery; Stereotactic surgery.

Figure 1:

Optical coherence tomography (OCT) scans before and after GKRS treatment. OCT is a technique that permits noninvasive cross-sectional imaging of the retina. All images were obtained using a CIRRUS 5000 instrument with Zeiss OCT-HD software v9.0.0.281. (a-c) Two weeks before GKRS. (d-f) Two weeks post-GKRS. (g-i) Two months post-GKRS. (j-l) Four months post-GKRS. (a, d, g, and j) The summary data of the scan, including RNFL (Retinal Nerve Fiber Layer) thickness, RNFL symmetry (coefficient calculated by comparing OD and OS RNFL tomography), and C/D (cup to disc) ratios. (b, e, h, and k) The OD (right eye) RNFL deviation map, based on an en face fundus image with machine drawn boundaries of the cup (red), disc (black), and RNFL calculation circle (purple). (c, d, i, and l) The same for OS (left eye).

Figure 2:

Gamma Knife radiosurgery dosage and localization plan. Treatment plan for GKRS irradiation using a Leksell Gamma Knife^® Perfexion^™ instrument. (a, c, and d) T1-weighted sequences with gadolinium contrast, while (b, e, and f) T2 weighted. Illustrated are the 12 gy (yellow) and 14 gy (green) isodose lines. Orientation as follows: (a and b) axial. (c and e) Coronal. (d and f) Sagittal.

Figure 3:

Magnetic resonance imaging (MRI) sequences before and after Gamma Knife stereotactic radiosurgery treatment. (a-d) MRI with contrast obtained 2 weeks before treatment. (e-h) MRI with contrast obtained 3 months posttreatment. Specific sequences (DWI, T2 weighted, SWAN, and postcontrast) are as delineated in the figure. Red arrow shows progression at tumor regression with treatment with top figures showing pretreatment and figures at the bottom showing post-treatment.