[Segmental arterial mediolysis : a differential diagnosis of vasculitis].

Segmental arterial mediolysis (SAM) is a rare non-atherosclerotic, non-inflammatory disease of unknown aetiology mostly affecting medium-sized arteries of the splanchnic circulation. Histologically, SAM is characterized by vacuolization and lysis of the arterial media leading to dissection, stenosis/occlusion or aneurysms. Symptoms vary from unspecific abdominal pain to hemorrhagic shock due to vessel rupture. The clinical and radiological presentation can mimic vasculitis, fibromuscular dysplasia or collagen vascular diseases. SAM is often self-limited and may be managed conservatively with adequate blood pressure control in the majority of cases. However, if arterial dissections or aneurysmal ruptures are present, endovascular or surgical treatment should be considered urgently.