Unusual erythema elevatum diutinum with fibrohistiocytic proliferation.

A 78-year-old woman with a history of symmetrical erythematous plaques on the arms, and a monoclonal gammopathy, developed a strange striped reticulate papular dermatosis with central atrophy. Histological examination was compatible with a very late stage of erythema elevatum diutinum (EED), showing a fibrohistiocytic proliferation with areas of granulation tissue. This fibrosis may result from the chronic dermal injury of leucocytoclastic vasculitis and is sometimes the predominant histology of EED. Investigations for underlying haematological anomalies, such as paraproteinaemia and infection with human immunodeficiency virus, must be performed. Dapsone is ineffective once the fibrous nodules have appeared.