The purpose of this report is to present the plain film and magnetic resonance imaging features in an unusual case of histologically-confirmed sarcoidosis involving the pelvis and spine.

Objectives: The aim of the study is to report a series of 17 cases of ankle bi-arthritis that occurred shortly after coronavirus disease 2019 RNA vaccination, and to discuss the potential role of these vaccines in the pathogenesis of this rheumatological manifestation. Methods: All patients were examined in the same department and received a full work-up to investigate the usual causes of ankle bi-arthritis. No rheumatic inflammatory disease occurred after 9 months of follow-up. A post-vaccination serological follow-up in search of anti-Spike antibodies was requested for all patients. Results: All patients recovered with low dose of prednisolone within <2 months, except one who could not be weaned off CS. The level of antibodies found was very high in all patients. Conclusion: The ankle bi-arthritis occurrence chronology, the follow-up and the similar clinical presentation might suggest a pathogenic role of RNA vaccination.