[A case of sarcoid myopathy presenting muscle pain and muscle weakness and with muscle MRI abnormality].

We experienced a 70-year-old female diagnosed as sarcoidosis. She complained bilateral femoral pain from 70-year-old. 3 months after the onset, she developed muscle weakness extending to her upper extremities with high fever of 38-39 degrees C. The erythema appeared at the right femoral region 4 months after the onset. She admitted to our hospital because of further evaluation. When she was admitted, she had tenderness on grasping the femoral muscles, proximal limb muscle weakness and Gowers' sign. On laboratory examination, CRP, aldorase, myoglobin, lysozyme were increased mildly. The EMG demonstrated a myogenic pattern. Muscle biopsy performed from the left quadriceps femoris muscle revealed non-caseating granuloma and muscle fiber necrosis. A diagnosis of muscle sarcoidosis was made from the biopsy findings and the clinical features. With oral prednisolone administration, muscle weakness and other clinical features improved gradually. On muscle MRI, multiple small high intensity areas were scattered in the femoral muscles. Muscle MRI is considered to be useful for differential diagnosis of muscle sarcoidosis.