Vacuolar Myopathy

Abstract

O CCASIONAL vacuolated muscle fibers may occur in any myopathy. Widespread vacuolation of muscle fibers occurs in familial periodic paralysis but only rarely has it been reported in other myopathies. Unverricht¹²described such a myopathy in 1891 and noted the absence of muscle-fiber regeneration. More recently, the absence of other structural changes in muscle fibers and the lack of focal inflammatory cell infiltrations have been noted in vacuolar myopathies by Pearson⁸and Denny-Brown.³Such myopathies have been reported in association with systemic lupus erythematosus,⁸rheumatoid arthritis, and carcinoma and following adrenosteroid therapy,¹or prolonged chloroquine phosphate therapy.¹⁵ This report is the summary of the clinical features of a case of vacuolar myopathy associated with systemic lupus erythematosus and prolonged chloroquine therapy. Light- and electron-microscopic appearances of the myopathy have been studied from biopsy specimens before and after discontinuation of the chloroquine and institution of