Polymyositis With Intranuclear Inclusions

Abstract
Eosinophilic nuclear inclusions were observed in skeletal muscles from a 52-yearold man with a slowly progressive polymyositis. Ultrastructurally the inclusions were composed of compact bundles of 70-Angstrom-wide filaments and were confined to myofiber nuclei. The filamentous inclusions appear to be unusually large examples of the intranuclear fibrillary bodies that have been described in many types of normal and abnormal cells. Thus, inclusions encountered in cases of myositis may be derived from several different sources despite their common light microscopic appearance.