Traumatic dissecting aneurysm of pericallosal artery following repetitive head trauma from horse riding treated by coil embolization: a case report

Background: Traumatic dissecting aneurysms of the pericallosal artery are extremely rare and carry a substantial risk of delayed rupture. Diagnostic confirmation can be challenging, and treatment is technically demanding given the small-caliber, fragile parent vessel wall. This report describes a dissecting pericallosal artery aneurysm presenting after horse-riding-related head trauma.

Case Description: We report the case of a 23-year-old woman without hypertension or smoking history who presented with acute severe headache and transient loss of consciousness after a direct head impact from her horse. Non-contrast computed tomography (CT) and CT angiography (CTA) revealed a wide-neck aneurysm of the left pericallosal artery without hemorrhage. Digital subtraction angiography confirmed a dissecting morphology of the pericallosal artery aneurysm along with a focal proximal stenosis. After interdisciplinary discussion in a neurovascular conference and informed shared decision-making with the patient, an endovascular strategy was selected. The combination of a fragile aneurysm wall, the proximal stenosis limiting catheter manipulation, and the unfavorable distal location posed significant technical challenges. Transfemoral coil embolization using two coils achieved complete occlusion without complications. Post-procedural magnetic resonance imaging (MRI) showed no ischemic sequelae. Follow-up MRI at 10 months showed consistent aneurysm occlusion and revealed multifocal microbleeds suggestive of chronic repetitive traumatic axonal shear injury.

Conclusions: Repetitive head acceleration and impacts during horse riding may represent an under-recognized mechanism for traumatic pericallosal artery dissecting aneurysms. Despite the challenging parent vessel anatomy, endovascular coil embolization can achieve complete aneurysm occlusion with no evidence of recurrence at 10-month follow-up. Long-term imaging surveillance remains essential.