Sarcoidosis is only rarely associated with symptomatic muscle disease, for example reported in four out of 800 patients and in two out of 500 patients in two series, and in isolated reports subsequently . Silverstein suggests that three patterns of symptomatic sarcoid muscle disease may exist, namely palpable muscle nodules, acute myositis and chronic myopathy, though states that considerably overlap may exist, as demonstrated in our case. Our patient's presentation with acute myositis is typical of other cases in that he was young, had a short history of muscle symptoms and was otherwise healthy with few other features of sarcoidosis, with the exception of the chest radiograph and serum ACE, which was increased. In this situation the muscle biopsy is crucial to the diagnosis in showing a granulomatous myositis with an inflammatory infiltrate and associated muscle necrosis and regeneration. In contrast in systemic sarcoidosis the finding of nonâ€caseating granulomas in biopsies from asymptomatic muscle, with no evidence of myocyte damage, is common and is reported in 50 to 80% of cases . We have two other cases of sarcoid myositis in our series, one of which illustrates the additional association of dermatomyositis with sarcoidosis, seemingly particularly prevalent in Japanese patients .
The delayed development of nodular sarcoid myositis in our case is interesting, and illustrates the overlap between forms of symptomatic sarcoid muscle disease over time. As an isolated presentation, nodular sarcoid myositis should be discriminated from focal myositis, which is also a very rare and usually selfâ€limiting benign disease .
This case illustrates that sarcoid muscle and lung disease often responds well to prednisolone . This is in contrast to the outcome of interstitial lung disease in association with idiopathic inflammatory myositis (1 antibody) where the outcome is less certain, particularly if the CK is normal . View larger version:Case 4. (A) Inversion recovery MR images of forearm showing multiple regions of increased signal intensity, indicating increased water content. (B) T1weighted images show that the oedematous muscles are iso intense with normal muscle. Case 4. Haematoxylin and eosin section of muscle showing a granulomatous myositis with a marked interstitial inflammatory infiltrate consisting mainly of lymphocytes, and aggregates of multinucleated giant cells (arrows).