Review of isolated ascending aortitis: differential diagnosis, including syphilitic, Takayasu's and giant cell aortitis.

The image of tree-barking and proximal aortic root dilatation is firmly entrenched in the minds of practising pathologists as representing syphilis until proven otherwise. We discuss the differential diagnosis of syphilitic aortitis, Takayasu's disease, and giant cell aortitis, with a review of the literature and brief overview of other types of aortitis. As a starting point, we report a case of non-specific, or idiopathic, aortitis with aneurysm that was initially misdiagnosed as syphilitic aortitis. We then review the literature and emphasise the lack of histological data and histopathological criteria for the diagnosis of non-infectious aortitis and the implications for treatment in cases of isolated aortitis. Tree-barking is a non-specific finding in aortitis of any aetiology, and syphilitic aortitis in developed countries is rare. It is still unclear if there are histological features that separate Takayasu's disease and giant cell arteritis. In the majority of patients presenting with aortic root aneurysms, aortitis is an isolated finding not associated with autoimmune disease. Despite a plethora of literature, a histological classification of aortitis has yet to be attempted.