Erythema elevatum diutinum.

A 64-year-old woman presented with a one-and-one-half year history of an enlarging, red-brown, firm plaque on the left thigh, with numerous, scattered, indurated, hyperpigmented patches on the lower extremities. Histopathologic examination of the largest plaque confirmed the diagnosis of erythema elevatum diutinum, which is a rare form of leukocytoclastic vasculitis that is associated with many disease entities, which include human immunodeficiency virus infection, malignant conditions, hematologic abnormalities, chronic infection, and autoimmune and connective-tissue disorders. The treatment of choice is dapsone; however, several other treatment modalities have been reported to be of benefit.