Bilateral giant internal carotid artery aneurysms in a child with suspected phacomatosis: a rare case report of arterial dysplasia

Abstract Pediatric intracranial aneurysms are exceptionally rare, especially in children under five years of age, and often differ from adult forms in etiology, morphology, and clinical presentation. They are more likely to be fusiform, giant, or thrombosed and frequently associated with congenital vascular anomalies or underlying genetic disorders. Early recognition is critical to prevent irreversible neurological damage or life-threatening complications. We report the case of a 4-year-old boy who presented with progressive left-sided ptosis, ophthalmoplegia, and optic atrophy. Neuroimaging revealed a partially thrombosed giant aneurysm of the left internal carotid artery (ICA), a patent fusiform aneurysm of the right ICA, and extensive arterial tortuosity with segmental ectasia and tortuosity. Additional findings included enlarged posterior fossa subarachnoid spaces, subcutaneous frontal veinous ectasia with transdiploic venous drainage, and arteriovenous shunts in the external carotid territory. Despite café-au-lait macules, the patient did not meet the diagnostic criteria for neurofibromatosis type 1. Digital subtraction angiography confirmed cervical occlusion of the left ICA and collateral compensation via the anterior communicating artery. The vascular pattern raised suspicion for a hereditary connective tissue disorder, such as Loeys–Dietz or vascular Ehlers–Danlos syndrome. PHACES-like vasculopathy was also considered due to the posterior fossa findings and cerebrovascular anomalies. Given the absence of rupture, preserved cerebral perfusion, and high interventional risk related to diffuse vascular tortuosity, a conservative approach with close clinical and radiological follow-up was adopted. Multidisciplinary input guided the decision-making process. Genetic testing could not be performed due to resource limitations. This case underscores the importance and role of neurovascular imaging and a broad differential diagnosis when evaluating cranial neuropathies in children. The presence of bilateral aneurysms, arterial tortuosity, and extracranial vascular anomalies should prompt investigation for syndromic arteriopathies. Multidisciplinary management and long-term monitoring are essential in such complex pediatric presentations.