Osseous sarcoidosis: a multicenter case-control study

International audienceObjective: To describe the clinical presentation, distribution of lesions, treatment, and outcomes of osseous sarcoidosis.Methods: A French retrospective multicenter study of patients with biopsy-proven sarcoidosis analyzed patients with 1) a biopsy-proven granuloma without caseous necrosis, and either 2) osseous clinical manifestations, or 3) abnormal osseous imaging. Sarcoidosis patients with osseous involvement (cases) were compared with 264 age- and sex-matched sarcoidosis patients with no osseous manifestations (controls).Results: In the osseous sarcoidosis group (n = 88), forty-two (48%) patients had osseous-related symptoms involving the axial (69%) and/or appendicular (58%) skeleton. On imaging, the most commonly affected bones were in the spine (52%), pelvis (42%), hands (22%) and femur (19%). Compared with controls, cases had higher rates of mediastinal (93% vs. 47%) and extra-thoracic lymph node involvement (66% vs. 21%), pulmonary (90% vs. 65%) and cutaneous involvement (44% vs. 23%) (all P < 0.0001), and hypercalcemia (8.5% vs. 2%, P = 0.014). Spleen/liver and gastrointestinal involvement were less frequent in the osseous sarcoidosis group (29% vs. 45%, and 1% vs. 17%, respectively, P < 0.0001). Response rates to with glucocorticoids alone, glucocorticoids plus methotrexate or glucocorticoids plus hydroxychloroquine were 23/44 (52%), 9/13 (69%) and 4/6 (67%), respectively.Conclusion: In patients with osseous sarcoidosis the spine and pelvis were the most commonly affected bones. Compared with controls, cases with osseous sarcoidosis have higher rates of thoracic and extra-thoracic lymph node involvement, pulmonary and cutaneous involvement, and hypercalcemia. Most patients with osseous sarcoidosis had a good response to glucocorticoids in combination with methotrexate or hydroxychloroquine