Isolated periaortitis

Isolated periaortitis is a non-aneurysmal form of chronic periaortitis.

Clinical features

• pain
• fever
• fatigue
• weight loss
• anaemia
• mesenteric arterial ischaemia: abdominal pain, diarrhoea, and gastrointestinal hemorrhage 
• renal artery stenosis: renovascular hypertension 
• vascular impairment depending on which other vessels are involved

Pathology

Periaortitis may be a local immune response to antigens like oxidised low density lipoproteins and ceroid found in the atherosclerotic plaques of the abdominal aorta. Some cases are due to IgG4-related disease. The disease tends primarily to involve the vascular structures causing stenosis of the major branches of the abdominal aorta (e.g. coeliac trunk, superior mesenteric artery, renal arteries).

Radiographic features

CT

• low-density periaortic enhancing mantle of soft tissue with or without aortic dilatation
• abdominal aorta and its major branches appear tomay be narrowed.

MRI

Signal characteristics of affected regions include:

• T1: hypointense  
• T2: hyperintense 
• C+ (Gd): intense enhancement 

PET

PET scan with 18F-fluorodeoxyglucose is an excellent tool in assessing the metabolic activity of the mass, detecting other sites of inflammation and disclosing infectious or neoplastic lesions with which periaortitis may be associated.

Treatment and prognosis

Steroids are usually effective and induce remission of the clinical symptoms, normalization of the acute-phase reaction, reduction in size of the retroperitoneal mass and also resolution of the obstructive complications. A number of immunosuppressive drugs, such as azathioprine, cyclophosphamide, and methotrexate, have been used as steroid-sparing agents or in patients not responding to steroids alone or when steroids cannot be tapered.