Thoracic Lymphoplasmacytic Aortitis Is Often Associated with IgG4-Related Systemic Disease
JR Stone, A Khosroshahi, V Deshpande, JH Stone. Massachusetts General Hospital and Harvard Medical School, Boston, MA
Background: We hypothesized that IgG4-related systemic disease accounts for a subset of cases of thoracic aortitis and for a significant fraction lymphoplasmacytic thoracic aortitis cases. To test this hypothesis, we reviewed the experience at our institution with thoracic aortitis over a five-year period. We also sought to establish pathologic criteria for identifying involvement of the thoracic aorta by this disorder.
Design: We searched our Pathology Service database to identify all patients with non-infectious thoracic aortitis who underwent resection over a 5-year time span. The inclusion criterion was the presence of chronic inflammation that was not characteristic of either atherosclerosis or aortic dissection. The exclusion criteria were a history of previous aortic surgery or evidence of an infectious aortitis. We subclassified the non-infectious aortitis cases into two categories based on the nature of the inflammatory component. Those cases with granulomatous inflammation with or without a significant plasma cell component were classified broadly as “granulomatous”. Cases with lymphoplasmacytic infiltrates in which granulomatous inflammation was absent were classified as lymphoplasmacytic aortitis. All cases of lymphoplasmacytic aortitis along with representative cases of giant cell aortitis and atherosclerosis were stained by immunohistochemistry for IgG4 and CD138, and the fraction of plasma cells that stained for IgG4 was determined.
Results: Of 638 resected thoracic aortas, 33 (5.2%) contained non-infectious aortitis. Four of these cases (12% of all patients with non-infectious aortitis) had histologic features of lymphoplasmacytic aortitis. Three of those four cases (9% of non-infectious aortitis cases) demonstrated pathologic involvement by IgG4-related systemic disease. Among those three cases, an elevated proportion of plasma cells (0.82±0.08) stained for IgG4, compared with cases of giant cell aortitis (0.18±0.13) and atherosclerosis (0.19±0.08) (P < 0.00001). Follow-up in two of these patients confirmed systemic involvement by IgG4-related systemic disease.
Conclusions: IgG4-related systemic disease accounted for 75% of lymphoplasmacytic aortitis cases and approximately 9% of all cases of non-infectious thoracic aortitis in our institution during a five-year period. Immunohistochemical assessment of the percentage of plasma cells that stain for IgG4 in resected aortas is helpful in identifying patients who have IgG4-related systemic disease.
Monday, March 22, 2010 11:30 AM
Platform Session: Section G 2, Monday Morning