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Int J Clin Exp Pathol 2013;6(9):1713-1722

Original Article
Inflammatory thoracic aortic aneurysm (lymphoplasmacytic thoracic aortitis): a 13-year-
experience at a German Heart Center with emphasis on possible role of IgG4

Abbas Agaimy, Michael Weyand, Thomas Strecker

Institute of Pathology, Center of Cardiac Surgery, Friedrich-Alexander-University, Erlangen, Germany

Received July 1, 2013; Accepted July 20, 2013; Epub August 15, 2013; Published September 1, 2013

Abstract: Background & aim: Aortic aneurysms represent one of the major causes of cardiovascular surgery. Their etiology varies greatly
based on patient’s age and other clinicopathologic determinants. In addition to common atherosclerotic vascular diseases, an inflammatory
etiology, in particular IgG4-related disease (IgG4-RD) has increasingly emerged as a cause of dissecting inflammatory aortic aneurysms (IAA).
Methods: To assess the frequency and types of IAA, we reviewed all cases of aortic aneurysms resected at our Erlangen Heart Center during
2000-2013. Results: 376 patients underwent resection of aortic aneurysms in the study period. These are further categorized as ascending
aortic aneurysms (45%), aortic arch aneurysm (2%), descending aortic aneurysm (3%), type A dissection (46%) and type B dissection (4%).
Fifteen cases (4%) showed variable lymphoplasmacytic inflammation thus qualifying as IAA. Affected were 9 females and 6 males (female to
male ratio = 1.5:1; age range: 52-80 yrs; mean: 70 yrs; median: 72 yrs). None was known to have IgG4-RD and serum IgG4 and/or IgG levels
(known in 6 cases) were normal. Variable sclerosing lymphoplasmacytic inflammation was seen either confined to the adventitia (periaortitis;
mainly in males) or extending through all layers (mainly in females). A wide range of IgG4 plasma cells (range: 3-182/HPF; mean: 51/HPF) and
IgG4: IgG ratios (range: 0.02 to 0.91; mean: 0.37) were detected. All but one of the cases with at least focally transmural inflammation showed a
higher IgG4: IgG ratios in excess of 0.3 (range, 0.32-0.91; median, 0.62). Lymphoid follicle and variable fibrosis were common but obliterative
phlebitis was not seen. Conclusion: IgG4-rich sclerosing lymphoplasmacytic thoracic aortitis is a constant histological feature of thoracic IAA.
Normal serum IgG4 in most patients, predilection for women and absence of other features of IgG4-RD all suggest a tissue-specific localized
autoimmunological process and argue against a systemic disorder. The relationship (if any) of IgG4-rich lymphoplasmacytic thoracic aortitis in
those patients with IAA lacking other organ manifestations or an elevated serum IgG4 level to systemic IgG4-RD remains unclear and merit
further studies.

Keywords: Inflammatory aortic aneurysms, lymphoplasmacytic thoracic aortitis, aortic dissection, IgG4, IgG4-related disease, periaortitis

Address correspondence to: Dr. Abbas Agaimy, Institute of Pathology, Friedrich-Alexander-University, Krankenhausstrasse 8-10, 91054
Erlangen, Germany. Tel: +49-9131-85-22288; Fax: +49-9131-85-24745; E-mail: abbas.agaimy@uk-erlangen.de