Clinical characteristics and outcome in muscular sarcoidosis: a retrospective cohort study and literature review

Abstract

We evaluated the clinical features and treatment response of patients with muscular sarcoidosis. A retrospective cohort of 12 patients showed muscle weakness in 11 and myalgia in seven. One had focal myositis. Four had a negative medical history for sarcoidosis. Muscle imaging showed muscle edema in all and replacement of muscle tissue by fat in half of patients. Muscle biopsy showed non-caseating granulomas in six of nine patients and inflammation without granulomas in three. None of the muscle biopsies showed features of inclusion body myositis. Imaging in three patients without muscle biopsy showed focal intramuscular masses or a ‘tiger man’ appearance typical for muscular sarcoidosis. Treatment consisted of glucocorticoids in 11, additional methotrexate or azathioprine in seven and infliximab in two patients. Half of the patients had symptoms leading to substantial disability (modified Rankin scale score >1) at last follow-up. A literature review of articles describing more than one muscular sarcoidosis patient published in the last 25 years identified 153 additional patients. We found muscular sarcoidosis to be a rare and often disabling disease which may be recognized by typical muscle imaging characteristics and add focal myositis to the muscular phenotypes of sarcoidosis.