Segmental arterial mediolysis and fibromuscular dysplasia: what comes first, the chicken or the egg?

Area of Science:

• Vascular Biology
• Pathology
• Medical Science

Background:

• Segmental arterial mediolysis (SAM) is a rare vasculopathy affecting splanchnic arteries, characterized by medial lysis and pseudoaneurysm formation.
• The pathogenesis of SAM remains poorly understood, with its relationship to fibromuscular dysplasia (FMD) debated.
• Healed SAM lesions share histological similarities with FMD, leading to hypotheses of SAM as a precursor to FMD.

Observation:

• A case of fatal SAM in a 61-year-old woman was investigated.
• Histological examination of the aorta revealed an unclassified "FMD-like" arteriopathy.
• This arteriopathy was observed to precede the development of SAM.

Findings:

• The findings suggest an "FMD-like" arteriopathy may precede SAM.
• This observation challenges the prevailing theory that SAM is a precursor to FMD.
• The study highlights a potential reversed pathogenetic relationship between these vascular disorders.

Implications:

• This case provides novel insights into the pathogenesis of SAM.
• Understanding the relationship between FMD-like arteriopathy and SAM is crucial for diagnosis and treatment.
• Further research is needed to elucidate the complex pathogenetic pathways involved in these rare vasculopathies.