Inclusion body myositis in post-poliomyelitis muscular atrophy.

A 38-year-old male developed a new muscle weakness in his left thigh 35 years after having acute paralytic poliomyelitis with residual right distal leg weakness and atrophy. EMG studies showed widespread denervation in proximal and distal muscles regardless the clinical involvement. Muscle biopsy from an affected muscle showed the findings of inclusion-body myositis consisting of perivascular and interstitial mononuclear infiltration, sarcoplasmic granular inclusions with membranous whorls and typical filamentous inclusions in several myonuclei. This raises the possibility of inclusion body myositis in other cases of progressive post-poliomyelitis muscular atrophy, especially those with perivascular infiltration of mononuclear cells in the muscle biopsy.