title: Fever of unknown origin: large vessel vasculitis diagnosed by PET/CT.
abstract: PET/CT is starting to play an important role in evaluating fever of unknown origin (FUO), due to its ability to localize and delineate areas of high metabolic activity, such as neoplastic proliferation and inflammation, including vasculitis. We present a case of giant cell arteritis (GCA) in a 72-year-old female patient admitted to our department with a 4-month history of FUO, weight loss and fatigue, without specific symptoms or signs. Laboratory investigations suggested acute phase response, with a pronounced erythrocyte sedimentation rate, high CRP level and microcytic anemia. A thorough diagnostic evaluation was performed to exclude an unknown primary tumor, which was initially suspected due to a positive family history of cancer. Surprisingly, PET/CT revealed large vessel vasculitis affecting the ascending, descending and abdominal aorta, as well as subclavian, proximal brachial and carotid arteries bilaterally. Biopsy of the superficial temporal artery confirmed the diagnosis of GCA. Treatment with methylprednisolone and azathioprine led to resolution of clinical symptoms and normalization of laboratory parameters. In addition to the use of PET/CT in the evaluation of FUO, its value as a method complementary to temporal artery biopsy is also discussed.
authors.affiliation: Division of Clinical Immunology and Rheumatology, Department of Internal Medicine, University Hospital Centre Zagreb, University of Zagreb School of Medicine, Kispaticeva 12, Zagreb, Croatia.
authors.forename: Dubravka
authors.initials: D
authors.lastname: Bosnić
authors.forename: Marko
authors.initials: M
authors.lastname: Barešić
authors.forename: Ivan
authors.initials: I
authors.lastname: Padjen
authors.forename: Antonija
authors.initials: A
authors.lastname: Balenović
authors.forename: Kamelija
authors.initials: K
authors.lastname: Zarković
authors.forename: Branimir
authors.initials: B
authors.lastname: Anić
mesh_terms: D000368:Aged; D005260:Female; D005335:Fever of Unknown Origin / Q000175:diagnosis*; D013700:Giant Cell Arteritis / Q000175:diagnosis*; D006801:Humans; D049268:Positron-Emission Tomography / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*