Recurrent Posterior Circulation Infarction with Vertebral Artery Beading and Occlusion in a Patient with Prior Segmental Arterial Mediolysis: A Case Report

Segmental arterial mediolysis is a rare, nonatherosclerotic, noninflammatory arteriopathy characterized by lytic degeneration of the arterial media. Although segmental arterial mediolysis typically involves the splanchnic circulation, craniocervical vascular abnormalities have also been reported. We report a 52-year-old Japanese man with a prior abdominal presentation highly suggestive of segmental arterial mediolysis who presented 5 years later with acute vertigo, vomiting, and truncal ataxia. Neurological examination was consistent with left lateral medullary syndrome. Magnetic resonance imaging demonstrated acute infarction in the left posterior inferior cerebellar artery (PICA) territory, with a chronic infarct in the same territory. Because brain magnetic resonance imaging had not been obtained during a transient episode of vertigo and gait instability 5 years earlier, this finding raised the possibility of a prior clinically unrecognized ischemic event. Magnetic resonance angiography showed poor visualization of the left vertebral artery. Computed tomography angiography, three-dimensional T2-weighted volume isotropic turbo spin-echo acquisition, non-contrast black-blood vessel wall imaging, and digital subtraction angiography demonstrated left vertebral artery origin occlusion, distal collateral reconstitution, distal beading-like changes, and vascular abnormalities near the posterior inferior cerebellar artery origin, suggesting impaired perfusion to the infarct territory. These findings suggested chronic dissecting and reparative changes in a nonatherosclerotic arteriopathy, including possible cerebrovascular involvement of segmental arterial mediolysis, although causality could not be established. The patient improved with conservative treatment and was discharged with a modified Rankin Scale score of 1. This case illustrates a possible delayed ischemic/occlusive phenotype and suggests considering craniocervical vascular evaluation in patients with visceral segmental arterial mediolysis who develop neurological symptoms.