Maximizing safety in the treatment of a large choroidal fissure arteriovenous malformation: The essential role of anatomy, staged embolization, and microsurgical technique.

Background: Arteriovenous malformations (AVMs) are complex congenital pathologies that require a deep understanding of their angioarchitecture and the involved brain anatomy. The ones within the temporal horn of the lateral ventricle present significant challenges for microsurgical treatment due to their deep location and proximity to critical neurovascular structures. These rare AVMs typically manifest with seizures or hemorrhage. They have afferents from the choroidal arteries, with arterial supply often arising from both the anterior and posterior circulations through the choroidal arteries, and exclusively deep venous drainage. Case Description: We report the case of a 44-year-old woman with a 1-year history of focal impaired awareness seizures accompanied by parosmia, headache, and tinnitus. She had no prior medical history. Magnetic resonance imaging and digital subtraction angiography identified an AVM located in the temporal choroidal fissure of the right lateral ventricle, with associated venous hypertension. Given the AVM's high-flow dynamics, nidus size, and deep location, a staged treatment approach was implemented. The patient underwent two pre-operative embolization sessions aimed at reducing blood flow within the AVM, decreasing venous pressure in the draining vein, and facilitating safer manipulation during surgery with a lower risk of intraoperative bleeding. Subsequently, microsurgical resection was performed through a trans-inferior temporal gyrus approach. Intraoperative identification of intraventricular structures and their anatomical relationships was paramount for safely managing the AVM. Postoperatively, the patient experienced temporary hemiparesis, which fully resolved within a few days, and showed significant improvement in her pre-operative symptoms. Conclusion: The patient's favorable post-operative outcome, with complete resolution of symptoms and no long-term neurological deficits, underscores the importance of a tailored multidisciplinary strategy. This case highlights the utility of advanced imaging, staged interventions, and precise anatomical understanding in the successful treatment of rare and challenging intraventricular AVMs.