Erythema elevatum diutinum: a clinicopathological study of eight cases.

Erythema elevatum diutinum (EED) is a rare cutaneous condition that initially presents as leukocytoclastic vasculitis (LCCV) of the skin and later resolves with fibrosis. In addition to the LCCV, EED may show features reminiscent of other entities. For example, it may mimic lesions of dermatofibroma, granuloma annulare, granuloma faciale, or dermatitis herpetiformis. For this study, we reviewed the clinical records and 13 skin biopsies in eight patients with EED. One of the patients had concurrent pityriasis rubra pilaris, and another developed lesions of EED following and at the sites of mosquito bites; these associations have not been noted previously. In addition to such typical histopathological features as diffuse dermal involvement by neutrophils, eosinophils, and leukocytoclastic vasculitis, we also found two unusual patterns. The first was characterized by palisaded necrotizing granulomas, as previously described and associated with Churg-Strauss granuloma; the second condition simulated a pyogenicgranuloma--like lesion.