F-FDG PET/CT in bone sarcoidosis: an observational study.

Objective: Bone sarcoidosis is usually rare. Imaging procedures such as fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-FDG PET/CT) can reveal bone sarcoidosis with better sensitivity than conventional radiography. We aimed to describe bone sarcoidosis involvement detected with F-FDG PET/CT.

Methods: This was an observational retrospective study of individuals with pulmonary sarcoidosis who underwent F-FDG PET/CT. According to the ATS/ERS/WASOG criteria, sarcoidosis was diagnosed by the presence of clinical and/or imaging features of sarcoidosis and evidence of non-caseating epithelioid granulomas on a biopsy. We assessed clinical and F-FDG PET/CT characteristics.

Results: Data for 85 patients with sarcoidosis (56.5% female, median age 47 [range 21-80] years) were analyzed. The median follow-up was 4 years. Among 56 patients, sarcoidosis occurred in more than three organs. According to ATS/ERS/WASOG criteria, bone sarcoidosis was diagnosed in 12 (14%) patients. The spine was the most commonly affected location (92%, n = 11), followed by the pelvis (67%, n = 8), sternum (33%, n = 4), humerus (25%, n = 3), and fingers (17%, n = 2). Only peripheral adenopathy was associated with bone sarcoidosis (p = 0.04). Seven patients had a F-FDG PET/CT follow-up, all showing a decrease of bone lesions.

Conclusion: Bone sarcoidosis occurred in 14% of patients with sarcoidosis, affecting multiple bones and mostly the axial skeleton. F-FDG PET/CT seems a sensitive tool for diagnosis and follow-up of bone sarcoidosis.