Progressive thrombosed pseudoaneurysm following transarterial balloon embolization in traumatic carotid-cavernous fistula: From silent lesion to symptomatic mass

Background: Pseudoaneurysm formation is a known but often underrecognized long-term complication following balloon embolization for traumatic carotid-cavernous fistula (TCCF). While many pseudoaneurysms remain asymptomatic, progressive enlargement and thrombosis may lead to mass effect and delayed neurological manifestations, including seizures and visual disturbances. Case Description: We report the case of a 33-year-old man who presented with new-onset generalized tonic-clonic seizure and binocular visual disturbances 14 years after undergoing transarterial detachable balloon embolization for TCCF. Brain magnetic resonance imaging revealed a large, partially thrombosed pseudoaneurysm arising from the cavernous segment of the internal carotid artery, extending into the suprasellar region with compression of the optic chiasm and adjacent frontal lobe. Humphrey visual field testing demonstrated bitemporal hemianopia. The patient underwent successful endovascular stent-assisted coiling. Post-treatment follow-up showed marked improvement in visual fields and complete seizure resolution, with no evidence of aneurysmal recurrence at 3 years. Conclusion: This case highlights the importance of long-term surveillance following balloon embolization for TCCF. Delayed pseudoaneurysm growth may lead to significant neurological deficits years after initial treatment. Early recognition and appropriate endovascular intervention are essential to prevent irreversible complications and optimize patient outcomes.