Late-stage nodular erythema elevatum diutinum.

Erythema elevatum diutinum (EED) is a rare chronic vasculitic process of unknown etiology that presents as bilateral, symmetrical, periarticular, red-brown papules and plaques, often over dorsa of joints. Early histologic changes are characterized by leukocytoclastic vasculitis. With chronicity, the lesions develop dense neutrophilic infiltrate and fibrosis. We describe an unusual case of late-stage nodular EED present for 35 years in a seronegative 75-year-old man. Asymptomatic papules and plaques measuring from 0.7 to 9.0 cm were seen over the interphalangeal joints, elbows, knees, and ankles. The histologic findings were characterized by predominant concentric fibrosis that formed well-circumscribed dermal and subcutaneous nodules. Awareness of this unusual presentation of EED helps to avoid misdiagnosis as cutaneous neoplasms.