18F-FDG PET/CT in bone sarcoidosis: an observational study

Abstract

Objective Bone sarcoidosis is usually rare. Imaging procedures such as fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) can reveal bone sarcoidosis with better sensitivity than conventional radiography. We aimed to describe bone sarcoidosis involvement detected with ¹⁸F-FDG PET/CT. Methods This was an observational retrospective study of individuals with pulmonary sarcoidosis who underwent ¹⁸F-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 ¹⁸F-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 ¹⁸F-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. ¹⁸F-FDG PET/CT seems a sensitive tool for diagnosis and follow-up of bone sarcoidosis. Key Points • Bone sarcoidosis is not rare. • Bone sarcoidosis affects mainly the axial skeleton. • ¹⁸F-FDG PET/CT is useful for diagnosis and follow-up of bone sarcoidosis.