Sequential aneurysms with incidental persistent primitive trigeminal artery: Is this association purely coincidental? A case study and review of the literature in search for a pathobiological mechanism

BACKGROUND: The appearance of sequential bilateral aneurysms in patients with persistent primitive trigeminal artery (PTA) is not described in the literature. No clear guidelines on screening and follow-up of patients with incidental PTAs for the detection of associated lesions have been established. CASE DESCRIPTION: A 55-year-old lady presented with occasional headaches. Detailed evaluation showed a left ophthalmic segment internal carotid artery (ICA) aneurysm measuring (11.2 × 5.5) mm. A bovine aortic arch configuration (type III) and a persistent left PTA were identified. A pipeline flex flow diverter was placed and aneurysm was coiled. Follow-up angiography after 6 months showed a completely occluded aneurysm with preserved PTA and a new aneurysm in the right ICA ophthalmic segment measuring 3.5 × 1.5 mm. It was followed up serially with angiography which revealed significant increase in 6 months. The base measured 5.4 mm and two blebs 3.1 mm and 2.5 mm had appeared on the dome. A SUPRASS flow diverter was placed across this aneurysm. Serial follow-up showed complete occlusion of the left aneurysm and significant reduction in filling of the right aneurysm. A review of the literature identified 34 cases of incidental PTAs associated with 50 aneurysms with increased prevalence of anterior circulation aneurysms in patients with incidental PTA. CONCLUSION: Sequential angiography of a patient with incidental PTA and an ICA aneurysm shows presence of a new aneurysm in contralateral circulation and its progression in size and morphology. Detailed large-scale studies are needed to assess the impact of incidental PTA on aneurysm development and management.