Periaortic fibrosis, more commonly known as retroperitoneal fibrosis, is an uncommon disease that was first described in 1905 by Albaran [1] and further documented by Ormond in 1948 [2]. It is characterized by the progressive proliferation of connective tissue in the retroperitoneal space, specifically along the aorta [3,4].
To our knowledge, ours is the first report in the English-language literature describing the CT and 18F-FDG PET findings of periaortic fibrosis with isolated involvement of the thoracic aorta. In this article, we describe the CT and FDG PET findings of an unusual case of periaortic fibrosis around the descending thoracic aorta. Intense FDG uptake on PET scans caused a false diagnosis of malignant tumor.