A Case of Segmental Arterial Mediolysis of Multiple Visceral Arteries Following Anti-COVID-19 Vaccination: Late Complication or Rare Coincidence?

BACKGROUND Segmental arterial mediolysis (SAM) is a rare noninflammatory, nonatherosclerotic vascular disorder characterized by arterial media disruption. In conjunction with the SARS-CoV-2 infection or anti-COVID-19 vaccination, vascular disorders have been recognized as organ-specific immune-mediated complications, and the number of reported cases is gradually increasing. CASE REPORT A 68-year-old man presented with severe upper abdominal pain and nausea 58 days after a third injection of Pfizer-BioNTech anti-COVID-19 mRNA vaccination. An abdominal dynamic computed tomography angiography showed stenosis and dilatation of multiple visceral arteries, including the middle and right colic arteries. In the omental arteries, spindle-shaped dilatation and stenosis were identified. The left epiploic artery was not visualized, suggesting the development of occlusion due to arterial dissection. Based on these findings, SAM of multiple visceral arteries was diagnosed. Because the patient's vital condition was stable, treatment by observation, with restriction of daily living, was chosen. Seventy-five days later, the pathological lesions in the affected vessels spontaneously resolved. CONCLUSIONS While coincidence could not be completely excluded in this case, anti-COVID-19 mRNA vaccination should be noted for its potential association with SAM as a possible late complication.