Clinical Summary
A 79 year-old woman with reactive airways disease and systemic hypertension presented with increasing
dyspnea, fever and cough. A chest radiograph showed bilateral apical infiltrates and a dilated aorta.
Sputum cultures grew H. influenzae. Subsequent transesophageal echo showed
a 5.3 cm diameter ascending aortic aneurysm and marked aortic insufficiency. She underwent surgery at
which time a large aortic aneurysm involving the aortic root and ascending aorta was identified. The
aorta was normal distally. The wall was not obviously thickened, the aneurysm was resected and a graft
placed. The specimen received in pathology was an opened portion of aorta measuring 9.4 x 5.1 x 0.1 cm.
The endothelial surface was unremarkable.
Histologic Findings
Sections show a normal thickness aorta with marked medial degeneration and laminar necrosis,
characterized by patchy intensely eosinophilic medial foci devoid of nuclei. Many of these foci are
surrounded by a lymphohistiocytic inflammatory response that contains small numbers of multinucleated
giant cells. The intima shows mild fibrous thickening. The adventitia is of normal thickness and
contains scattered lymphoid aggregates. This case was originally signed out as "Giant Cell Aortitis."
The patient has continued to be followed at the Mayo Clinic and has had no other vascular symptoms,
evidence of temporal arteritis or a systemic inflammatory disease. She is alive and well four years
later and never received any systemic therapy for her disease.
Slide 9 - The low power image shows a normal thickness advantitia, moderate medial thickening and moderate fibrous intimal thickening.
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Slide 10 - The media contains foci of laminar necrosis rimmed with inflammatory cells.
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Slide 11 - The inflammatory infiltrate contains numerous lymphocytes, plasma cells, eosinophils and multinucleated giant cells. The wall does not contain significant fibrosis.
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Diagnosis
Idiopathic Aortitis with Giant Cells
Discussion
This case represents an example of idiopathic aortitis with giant cells. The patient had no symptoms
of a generalized vasculitis at the time of presentation with her aneurysm, nor has she developed symptoms
during the follow-up period, despite receiving no specific therapy, e.g. steroids. In an ongoing study
of the pathology of the aorta by our cardiovascular pathology group (Homme JL, et al), we identified 14
patients with similar clinical and histologic features (see figure ).
Among these patients there were 3 men and 11 women, with a mean age of 71 yrs. (50-82). All
presented with ascending aortic aneurysms, none with dissection. Eight patients had dyspnea, 4 had
back/chest pain, and 6 were asymptomatic; the only other symptoms were fever (1), fatigue (1), and
Raynaud's phenomenon. One patient received post-operative steroids. Twelve patients are alive and well
without ever having evidence of a systemic inflammatory process, and two have died of other causes with a
mean follow-up of 6.1 yrs (range 2-16).
Among the patients with idiopathic aortitis, the aortic wall was a mean of 0.4 cm thick. Laminar
medial necrosis was present in 50% of cases and in the majority of cases, giant cells were present
(64%).
The differential diagnosis includes other forms of non-infectious aortitis. Patients with Takayasu's
aortitis (TYA) are by definition younger than our patients with idiopathic aortitis. The mean age of
patients in our study with TYA was 28 yrs. The aortic specimens from patients with TYA were thicker
(mean 0.7 cm, range 0.4 cm – 0.9 cm) than those with either giant cell aortitis occurring in association
with temporal arteritis (0.3 cm) or idiopathic aortitis (0.4 cm). This was attributable primarily to
intimal and adventitial changes. All of our patients with TYA had giant cells. Laminar necrosis was
present in TYA, but was less common than in cases of idiopathic giant cell aortitis.
Features that help distinguish idiopathic giant cell aortitis from the aortitis associated with
temporal arteritis are primarily clinical. All of the patients with idiopathic aortitis had symptoms
only referable to their aortic disease. Among those with aortitis associated with temporal arteritis in
our series, 6 patients had a past history of temporal arteritis. Another 5 patients had 2 or more
symptoms of temporal arteritis (including such things as new onset headache, limb claudication,
paresthesia, synovitis, polymyalgia rheumatica, decreased pulses, bruits or a history of transient
ischemic attacks). One had a dissection. Among these 13, 76% were on steroids at the time of
presentation with their aortic disease. Histologically, however, the aortic disease in patients with
temporal arteritis and those with idiopathic aortitis were very similar.
Patients with idiopathic aortitis have rarely been mentioned in the literature. In a large study of
patients undergoing surgery for aortic disease, the authors of a Cleveland Clinic study (Royo-Leyva, et
al) identified 36 patients with aortitis not related to systemic disease. The mean age of the patients
was 65 yrs (range 36-79). Only 1 patient was younger than 40 years of age and 76% were women. All
presented with thoracic aneurysms. 44% of these patients had features of giant cell aortitis. Very
little else about these patients can be gleaned from the paper, however, and no details about the
histology are given. In a study examining the clinical characteristics of patients with temporal
arteritis who develop thoracic aortic aneurysms, Evans et al identified three patients who had developed
a thoracic aneurysm 4-7 yrs prior to receiving a diagnosis of temporal arteritis. Autopsy histology in
one showed a chronic dissection, but no inflammation. Histology was not available from the other two
patients. Therefore, it is not clear whether these patients had aortic disease related to their temporal
arteritis, or another process. They did not, however, have a history of systemic hypertension or other
risk factors for thoracic aneurysms.
The pathogenesis of the cases of idiopathic aortitis is unknown. The pathways responsible for the
development of temporal arteritis are just beginning to be understood. Molecular studies of patients
with temporal arteritis indicate that T-cells are recruited to the vessel wall, are activated locally,
produce IL-2 and IFN-gamma and regulate the activity of tissue-infiltrating macrophages. Effects of
T-cell activation include the production of proinflammatory cytokines, metalloproteinases and growth
factors such as platelet derived growth factor (PDGF). It is interesting that the amounts of these
factors in tissue varies among patients with temporal arteritis and can be correlated with differences in
clinical manifestations of disease. Perhaps similar studies done on aortic samples will help us better
understand the pathogenesis of disease in patients who with idiopathic giant cell aortitis.
In summary, idiopathic aortitis (with or without giant cells) appears to represent an isolated form of
vasculitis with a good short-term prognosis. If patients do not have a past history of temporal
arteritis or other inflammatory disease known to be associated with aortitis and lack symptoms of
temporal arteritis at the time of presentation, steroid therapy may not be necessary.
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