Pulsatile tinnitus is generally of vascular origin and can be due to arterial, venous, or systemic causes. While certain congenital anatomical variants and arterial vascular loops have been commonly found in symptomatic patients undergoing imaging, persistent primitive trigeminal artery in association with isolated tinnitus is unusual. Thus we report a patient with unilateral isolated pulsatile tinnitus who was evaluated with magnetic resonance angiography and was found to have a persistent primitive trigeminal artery. We also briefly discuss vascular tinnitus as well as the embryology, imaging, and classification of persistent primitive trigeminal artery with the clinical implications. 1. Introduction Tinnitus is typically a ringing sound in one or both ears in the absence of an external stimulus. It can either be pulsatile (synchronous with the patient’s pulse) or nonpulsatile. It can also be subjective (audible only to the patient) or objective (audible to both the patient and the examiner) [1]. Pulsatile tinnitus is generally of vascular origin and includes arterial, venous, and systemic causes [2]. Among the arterial causes, anatomical variants like aberrant internal carotid artery, laterally displaced carotid arteries, persistent stapedial artery, and vascular loops have a well-known association with tinnitus [3, 4]. We report a patient with an unusual cause of vascular pulsatile tinnitus, namely, persistent primitive trigeminal artery (PPTA), followed by a brief review of vascular tinnitus as well as PPTA. 2. Case Report Our case is a 48-year-old lady who was referred to our department with a long-standing history of unilateral left-sided pulsatile tinnitus for one year. There were no associated complaints such as trigeminal neuralgia, facial weakness, vertigo, or hearing deficits. Clinical and otoscopic examinations were normal. An arteriovenous vascular malformation was suspected, so she underwent a 3-tesla magnetic resonance (MR) imaging of brain and cerebellopontine angle along with a 3D time of flight (TOF) angiography in our hospital. MR and MRA base images show a serpiginous vessel (black arrows in Figures 1(a) and 1(b)) arising from the cavernous part of the left internal carotid artery (ICA), coursing posterior, and laterally around the dorsum sellae up to the basilar artery (BA) (white arrows in Figures 1(a) and 1(b)) in the prepontine cistern. This vessel is the primitive persistent trigeminal artery (PPTA) forming an anastomosis between the carotid and the basilar systems. The proximal basilar artery is hypoplastic (white arrow in
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