Erythema elevatum diutinum: an ultrastructural case study.

An electron microscopic study was made of a patient with erythema elevatum diutinum, a rare variant of cutaneous leukocytoclastic vasculitis. Biopsies were obtained from early evolving and late fibroproliferative lesions. Early lesions showed vasculitis and a massive dermal infiltrate composed mainly of neutrophils, histiocytes/macrophages and apparently increased Langerhans cells. Later lesions were characterized by a dense fibrosis with a proliferation of fibroblasts and myofibroblasts and a dermal infiltrate in which lymphocytes and histiocytes/macrophages predominated. Even in later lesions, dermal Langerhans cells were observed in great number. Langerhans cells may be involved in the evolution of this rare disease.