[Inclusion body myositis (IBM) -- a review]

Inclusion body myositis (IBM) is characterized by the insidious onset of slowly progressive proximal and distal weakness. The clinical hallmark of IBM are atrophy and weakness of the quadriceps and the wrist and finger flexors. Although frequently misdiagnosed, IBM is the most common inflammatory myopathy in patients over the age of 50 years. The diagnosis of IBM can be made, even in absence of a typical clinical history, exclusive on the basis of muscle biopsy when all of the characteristic histopathological findings are present (inflammation, rimmed vacuoles, protein deposits, and 15-18 nm tubofilaments). Apart from sporadic IBM there is a group of heterogeneous inherited myopathies with histopathologic similarities to sporadic IBM. Although some immunomodulating therapies may exert transient and mild benefits, there is no effective treatment for IBM.