[Bone sarcoidosis: an underrecognized manifestation of a multisystemic disease]

Bone sarcoidosis is a rare manifestation, reported in 1-15% of patients, and most often presenting as a multisystemic disease. Although it was historically described as predominantly affecting the phalanges (Perthes-Jüngling disease), axial involvement (spine, pelvis) is now recognized as frequent, most likely due to the increased use of MRI and PET-CT scans. This condition is often asymptomatic and discovered incidentally, but it can cause pain and disabling complications. Lesions can appear lytic, sclerotic, or mixed, with no specific radiological pattern. Definitive diagnosis relies on a bone or bone marrow biopsy demonstrating non-caseating granulomas and ruling out infection or malignancy. Treatment is not standardized and mainly relies on systemic glucocorticoids, with immunosuppressive agents added when necessary.