Within minutes following an altercation with police, a 55-year-old man noted onset of speech difficulty and right-sided weakness without headache or neck pain. Dysarthria and right hemiparesis (grade 4/5) without ocular disturbance was found. Left ventral hemipontine infarction was documented from the ipsilateral tortuous primitive trigeminal artery (figure). Cerebral angiogram failed to reveal underlying arterial dissection.
White arrow points to the primitive trigeminal artery (A–D). MRI, fluid-attenuated inversion recovery sequence, demonstrating the left ventral pontine infarction (A). Magnetic resonance angiography demonstrates proximal hypoplastic-stenotic vertebrobasilar system (B). Selective left internal carotid artery angiogram: lateral (C) and anteroposterior view (D) (same viewing angle as in B). Triangular arrowhead points to the left internal carotid artery (B–D).
Persistent anastomosis from a cavernous portion of internal cerebral artery to rostral basilar artery is unusual, with an estimated incidence of 0.2%.1 Although the artery has been implicated as a conduit of a carotid artery to posterior cerebral artery distribution embolic stroke,2 our case illustrates that localized occlusive process may also occur.