Idiopathic granulomatous myositis: Does the clinical spectrum include polymyalgia rheumatica?

Abstract

Granulomatous inflammation restricted to muscle is an uncommon cause of myopathic syndromes. Two patients were diagnosed with idiopathic granulomatous polymyositis after appropriate investigations failed to reveal a systemic or alternative explanation for the granulomas seen in their muscle biopsy. One patient presented with a syndrome indistinguishable from polymyalgia rheumatica but both patients manifested disabling myalgias which were strikingly corticosteroid responsive. The two cases underscore the potential importance of muscle biopsy in polymyalgic states, the non-specificity of polymyalgia rheumatica as a syndrome which can be simulated by other disorders including granulomatous myo..