[Erythema elevatum diutinum. I. Electron microscopy of a case with extracellular cholesterosis (author's transl)].

1. A typical case of Erythema elevatum diutinum (E.e.d.) with extracellular cholesterosis is described clinically and histologically in a 48-year-old woman. The disease had a course of 15 years. 2. Electron microscopy confirmed the histological and immunfluorescent findings of leucocytoclastic vasculitis. In older lesions, histiocytes/macrophages predominate. Intra- and extracellular lipid depositions showed a variety of ultrastructural characteristics which differed from electron microscopical findings described in other disorders associated with lipid deposition. 3. The findings are in accordance with the hypothesis that the primary event in E.e.d. is a special type of chronic leukocytoclastic vasculitis. Subsequently, the damage of the vessel walls and focal necrosis may lead to secondary lipid deposition.