2026 Poster Presentations
P129: INTRACRANIAL MENINGIOMA AT FORAMEN MAGNUM PRESENTING AS BOW HUNTER'S SYNDROME VIA V4 SEGMENT COMPRESSION
Paarth Patel, BSA; Jonathan Espinosa, MD; Jonathan Fisher, MD; Cristian Gragnaniello, MD, PhD; UT Health San Antonio
Introduction: Bow Hunter’s Syndrome (BHS) is a rare condition in which physiologic head rotation causes dynamic vertebral artery (VA) compression and vertebrobasilar insufficiency. Most reported cases are attributed to degenerative changes, particularly osteophytes and cervical spondylosis. A majority of which involve the V2–V3 segments of the VA. Tumor-related causes and compression of the distal segments of the VA are exceptionally uncommon. We present a novel case of BHS from a foramen magnum meningioma compressing the intradural V4 segment of the VA.
Methods: An elderly male with hypertension developed progressive fine-motor difficulty and episodic weakness triggered by head turning. Left rotation produced acute right hemiparesis, hemianesthesia, and dizziness; right rotation produced milder contralateral symptoms. MRI showed a homogeneously enhancing intradural extramedullary mass at the left foramen magnum displacing the VA and compressing the cervicomedullary junction (Figure 1). The patient underwent midline suboccipital craniotomy, C1 laminectomy, and partial occipital condylectomy with microsurgical resection under neuromonitoring and neuronavigation.
Figure 1. MRI brain T1 post-contrast sagittal (a) and axial (b) views of demonstrating a homogeneously enhancing intradural-extramedullary mass compressing the cervicomedullary junction (Blue arrow). The lesion is also seen compressing the left vertebral artery (red arrow).
Results: Gross total resection was achieved using ultrasonic debulking and coagulation of a broad lateral dural attachment, enabling complete decompression of the V4 segment and the cervicomedullary junction (Figure 2). Pathology confirmed WHO grade I meningioma. Postoperatively, hemiparesis, hemianesthesia, and dizziness resolved completely. Follow-up MRI showed no residual tumor and restoration of normal cervicomedullary and vascular relationships (Figure 3). Patient remained symptom-free at 2 and 6 weeks.
Figure 2. (a) Intraoperative image under the microscope of suboccipital craniotomy and a Y-shaped dural opening. An intradural mass is seen on the left side of the patient (black star). A thin layer of arachnoid is covering the medial aspect of the tumor. The tumor is abutting the right cerebellar tonsil (arrow). The dural attachment is located lateral to the dural leaflet (not visualized). (b) The telovelotonsillar segment of the right posterior inferior cerebellar artery (arrow) traversing over the right cerebellar tonsil is seen on the medial border of the tumor. The left cerebellar tonsil (star) is displaced superomedially by the tumor.
Figure 3. The tumor has been removed. The left vertebral artery is seen with atherosclerotic changes entering the dura (black arrow). The cervicomedullary junction (yellow arrow) is now fully decompressed. The left spinal accessory nerve (white arrow) is ascending through the foramen magnum.
Conclusion: This case demonstrates that BHS can arise from meningioma causing direct V4 compression, extending the spectrum of recognized etiologies. In this context, MRI delineation of the tumor and its effect on the VA supported surgical excision as the only definitive treatment. Posterior skull base decompression and tumor removal achieved both oncologic control and curative relief of BHS. This report emphasizes the consideration of unexpected causes such as intracranial masses in patients with positional vertebrobasilar symptoms, especially when imaging implicates the V4 segment.