An Electron Microscopic Study of a Case of Dermatomyositis

Abstract

Biopsy material from a case of dermatomyositis is examined. The calcified masses are adjacent to regions showing collagen fibrils, many of which are immature. The fibrils are sometimes considerably bent. The calcified material is identified, by electron diffraction, as apatite and its appearance is described. It is deduced that calcification consists mainly of a buildup of apatite in and on the collagen fibrils.