Coexistence of FDG-Avid and FDG-Negative Aneurysms in a Patient With Fever of Unknown Origin

Abstract

A 68-year-old man with intermittent fever of unknown origin for 5 months underwent 18F-FDG PET/CT to detect causative lesion. An 18F-FDG–avid lesion was revealed in the left pelvic iliac vessel region and was highly suggestive of malignancy. One and a half months later, a giant left internal iliac artery aneurysm was identified by CT angiography, corresponding to the 18F-FDG–avid lesion. Combined with elevated inflammatory markers, he was finally diagnosed as having inflammatory internal iliac artery aneurysm. An abdominal aortic aneurysm with low 18F-FDG uptake was also identified.