Chronic periaortitis: a large-vessel vasculitis?

Purpose of review Chronic periaortitis is characterized by a fibro-inflammatory process spreading from the abdominal aorta and the iliac arteries. Originally, chronic periaortitis was considered a localized inflammatory response to severe aortic atherosclerosis. However, subsequent studies have shown that chronic periaortitis may also involve other arteries and present with features of auto-immune diseases. This article reviews the issue of large-vessel involvement in chronic periaortitis and its implications in the pathogenesis and nosography of the disease. Recent findings In many reports, chronic periaortitis has been shown to involve not only the aorto-iliac axis but also other vascular segments such as the thoracic aorta, the proximal epiaortic arteries, the coronary, renal, and mesenteric arteries. Thoracic aorta involvement may manifest as thoracic periaortitis with or without aneurysmal dilatation, or simply as thoracic aorta aneurysm. Thoracic periaortitis can also be a feature of the so-called IgG4-related systemic disease, with which chronic periaortitis may sometimes be associated. Histopathologic studies of chronic periaortitis show adventitial inflammation and fibrosis, vasculitis of vasa vasorum, and adventitial lymphoid follicles with germinal centers, suggesting that chronic periaortitis could be a primary aortitis. Genetic studies have demonstrated an association with HLA-DRB1*03, a marker of auto-immunity, and with the CCR5Δ32 polymorphism, which has been mapped to a Th2 response. Taken together, these findings support the notion of a primary inflammatory or immune-mediated disorder. Summary Chronic periaortitis is an inflammatory or immune-mediated disorder characterized histopathologically by adventitial inflammation and clinically by variable involvement of different arteries, mainly of large caliber. These findings raise the issue of whether chronic periaortitis should be considered a large-vessel vasculitis.