Polymyositis With Facioscapulohumeral Distribution

Abstract

An 11-year-old girl rapidly developed weakness limited to facial and shoulder muscles with associated myoedema. The legs were not involved. Electromyography demonstrated myopathic motor unit potentials and increased muscle irritability. Serum enzyme levels were markedly elevated and returned towards normal with steroid therapy although clinical improvement was slight. Two muscle biopsies showed inflammatory reaction and necrosis. The short clinical course, absence of affected family members, and laboratory findings were consistent with a restricted polymyositis. Restricted muscle involvement simulating facio-S scapulohumeral dystrophy is an unusual variation of polymyositis.