Ultrastructural study of chronic lesions of erythema elevatum diutinum: "extracellular cholesterosis" is a misnomer.

Erythema elevatum diutinum (EED) is a rare disease of unknown origin that belongs to the spectrum of leukocytoclastic vasculitis. Chronic lesions of EED contain lipid deposits, for which the term extracellular cholesterosis has been coined. We studied a typical case of EED with long-standing lesions. Findings of electron microscopic examination revealed a heavy, exclusively intracellular lipid deposition that consisted of lipid droplets, myelin figures, and rare cholesterol clefts within histiocytes but also within epidermal keratinocytes, mast cells, pericytes, and lymphocytes. These findings are in keeping with the results of previous ultrastructural studies and suggest that the term extracellular cholesterosis is a misnomer; intracellular lipidosis would more accurately describe the lipid deposition.