Purpose of review: In last few years, there have been significant advances in our understanding of a newly recognized condition known as IgG4-related systemic disease. This review will focus on IgG4-related systemic disease as a cause of thoracic aortitis, inflammatory abdominal aortic aneurysm or periaortitis, and retroperitoneal fibrosis.
Recent findings: A significant fraction of thoracic lymphoplasmacytic aortitis cases, about 40% of inflammatory abdominal aortic aneurysms/abdominal periaortitis cases, and a portion of retroperitoneal fibrosis cases are all caused by IgG4-related systemic disease. Assessing pathologic specimens for the fraction of plasma cells that express IgG4 is useful in identifying patients with this disorder. Recently reported data may indicate IgG4-related aortic disease to be more common than widely realized.
Summary: IgG4-related systemic disease is a newly recognized disorder that may manifest as thoracic aortitis, inflammatory abdominal aortic aneurysm or retroperitoneal fibrosis. IgG4-related systemic disease should be considered in any patient found to have aortitis or periaortitis. Further studies into diagnostic criteria, disease prevalence, prognosis, therapeutic interventions, and differentiating possible localized hypersensitivity reactions from systemic disease are areas of active investigation. Criteria are presented for the pathologic diagnosis of IgG4-related aortitis.