[Muscular Sarcoidosis]

Muscular sarcoidosis is a granulomatous myopathy of unknown etiology characterized by the presence of non-caseating granulomas associated with sarcoidosis. Asymptomatic muscle involvement is revealed by imaging findings in majority of the patients with muscular sarcoidosis. Symptomatic muscular sarcoidosis, namely sarcoid myopathy, is a rare condition, and three distinct clinical types are recognized: nodular myopathy, acute myopathy, and chronic myopathy. Patients often present with myalgia, progressive weakness, and atrophy of the proximal muscles of the extremities. In order to confirm a diagnosis of sarcoid myopathy and distinguish it from other muscle disorders, muscle biopsy is the most effective and useful method even in the absence of weakness or myalgia. In addition, magnetic resonance imaging, gallium-67 citrate scintigraphy, and fluorodeoxyglucose-positron emission tomography provide significant information for diagnosis. Immunomodulatory therapy, including corticosteroids, plays an important role in preventing progression. However, effective therapeutic strategies for sarcoid myopathy have not been established yet and need to be explored in the future.