Anomalies in perifascicular muscle fibers as an differential-diagnostic criterion. I. Perifascicular atrophy in inflammatory myopathies.

Thirty-four cases of inflammatory muscle disease (21% from a collective of 160 inflammatory myopathies) were suitable for morphometric measurements. A statistical analysis of our data yields a perifascicular fiber atrophy (PA) in 50% of these cases. Morphometry was able to detect also cases with significant PA which were evaluated subjectively as normal. In dermatomyositis, the finding of a PA was more frequent than in other subgroups of inflammatory myopathies. There was also an accumulation of PA in patients with a paraneoplastic polymyositis. It could not be confirmed that PA occurs more frequent in dermatomyositis of children.