Inclusion body myositis masquerading as polymyositis: A case study

A case of inclusion body myositis masquerading as unresponsive polymyositis is presented. A 56-year-old woman diagnosed with "biopsy-proven" polymyosi tis in 1991 was referred to our clinic in 1997 with progressive, painless w eakness that was unresponsive to steroid therapy. Further evaluation, inclu ding electromyography and review of the original muscle biopsy specimen, fo und a diagnosis of inclusion body myositis, leading to a change in the pati ent's prognosis and management. Inclusion body myositis is frequently mista ken for polymyositis, despite the fact that it is now the most common infla mmatory myopathy affecting people older than 50 years. The purpose of this report is to increase awareness of this disease, to enhance early diagnosis , and to ensure appropriate management. We discuss the clinical findings, p athogenesis, and physiatric management, as well as compare this disease wit h other idiopathic inflammatory myopathies.