To the Editor:—Fever of unknown origin in patients with giant cell arteritis (GCA) who have neither cephalic symptoms nor histological evidence of temporal arteritis(TA) has, as it corollary, potentially life-threatening aortitis in patients with isolated polymyalgia rheumatica (PMR). In one study, in spite of isolated PMR, the latter characterised by absence of cephalic stigmata as well as by non-diagnostic temporal artery (TA) biopsy, aortitis was, nevertheless, an associated feature, documented by 18-fluorodeoxyglucose positron emission tomography. In other cases only absence of cephalic signs sufficed to characterise isolated PMR, and, in two such instances, aortitis was documented by nuclear magnetic resonance imaging. Diagnostic difficulty is compounded when there is neither cephalic nor PMR symptomatology, as in a 75-year-old woman in whom the only feature of GCA was progressive enlargement of an ascending thoracic aortic aneurysm, necessitating surgical treatment. Histology of the surgical specimen showed GCA. Presentation of giant cell arteritis solely with aortitis-related symptoms also characterised a 76-year-old patient with ascending aortic aneurysm in whom histology of the aneurysmal wall, again, revealed giant cell arteritis. Diagnostic difficulties notwithstanding, it is important to identify PMR-related aortitis, because patients with isolated PMR have significantly (p<0.05) increased risk of death from vascular disease, including ruptured aortic aneurysm. Oscar M. P. Jolobe, MRCP (UK), Manchester Medical Society, c/o John Rylands University Library, Oxford Road, Manchester M13 9 PP, UK (e-mail: firstname.lastname@example.org).