Wegener's granulomatosis overlapping with Takayasu's arteritis revealed by FDG-PET scan

We report the case of a 23-year-old woman who initially presented with Wegener's granulomatosis (WG) limited to the lungs, diagnosed on the basis of a biopsy of an upper left lobe nodule and elevated ANCA titers. Remission occurred under treatment with methylprednisolone and intravenous immunoglobulins. Later in the course of the disease, findings highly suggestive of Takayasu's arteritis (TA) appeared: murmur at the level of the left subclavian artery, thickening of the arterial wall of the aorta and pulmonary arteries on tomodensidometry, and abnormal uptake of the aortic arch and ascending aorta on FDG-PET scan. This latter exam also showed an increased uptake of an already known pulmonary nodule, due to WG. Although five cases of WG occurring together with TA have previously been reported, this is the only one in which TA was revealed by FDG-PET scan. In the specific setting of overlapping vasculitides, FDG-PET scan may be helpful in simultaneously evaluating the activity of the two diseases.