Necrobiosis lipoidica.

Necrobiosis lipoidica (NL) is a granulomatous condition with a degenerative connective tissue of unknown etiology very often associated with diabetes. Histopathologically, NL involves all of the dermis and, often, the subcutaneous fat produces a septal panniculitis. There are some changes suggesting the diagnosis of NL, and systemic disease should be considered if there is the presence of necrotizing vasculitis in the skin biopsy. Many theories of pathogenesis have been proposed, and many types of drugs are available for use in its treatment.