Dermatomyositis with universal calcinosis. A histopathological and electron optic study.

Biopsies from a 5-year-old girl with dermatomyositis and universal calcinosis were studied histopathologically and by means of electron optical techniques. The dermis was infiltrated by fibroblasts, lymphocytes and plasma cells. In the lower part of the dermis, dense basophilic areas were present. In the vicinity of these areas irregular elastic fibers appeared. In the electron microscope these elastic fibers appeared mineralized to varying degrees. The mineral part was identified as calcium apatite (either calcium-hydroxy-apatite or calcium fluoroapatite) by X-ray microanalysis and selected area diffraction. No calcification was observed outside the elastic fibers.