Case description
48-year-old male evaluated for progressive polyarthralgia, myalgias and weakness. Patient was initially evaluated by Rheumatology. Laboratory studies revealed multiple positive antinuclear antibodies (ANA’s), positive ribonucleoproteins (RNP), SSA antibody, rheumatoid factor (RF), anti-neutrophil cytoplasmic antibodies (ANCA) and myeloperoxidase (MPO). Differentials included discoid lupus, systemic lupus erythematosus versus mixed connective tissue given positive RNP treated with Plaquenil. He had a good response to few rounds of steroids. EMG was ordered revealing diffuse active myositis. Neurology was subsequently formally involved. Exam was significant for proximal more than distal muscles, muscle atrophy, contractures at the finger flexor joints, limitation with ambulation and inability to stand without assistance. Respiratory symptoms prompted chest tomography which revealed hilar adenopathy. There was muscle edema on magnetic resonance. Muscle biopsy was notable for non-caseating granulomatous myositis confirming diagnosis of sarcoid myositis. Clinical improvement after chronic steroids were started. Alternative treatment considered was infliximab.
Discussion
Sarcoidosis is a multisystem chronic granulomatous disease most commonly affecting the lungs. Musculoskeletal manifestations occur in 20% of patients affecting mainly bone and rarely having isolated myopathy. Reports of random muscle biopsies in patients with systemic sarcoidosis have shown noncaseating granulomas in 32-80% of them. For extrapulmonary sarcoidosis, PET/CT and MRI are useful. Tissue biopsy will assist in providing a definitive diagnosis. Treatment is with steroids and/or steroid sparing immunosuppressants.