Chest pain in a mid-aged woman, not simply myopericarditis: a case report of anti-Ku positive polymyositis.

This report presents a rare case with anti-Ku positive polymyositis and the cardiac involvement of polymyositis was manifested as myopericarditis. Therefore, positive anti-Ku might explain the myopericarditis as cardiac involvement in polymyositis. More cases and longer duration of follow-up is required for the comprehensive understanding of the disease.