Concomitant granuloma annulare and necrobiosis lipoidica. Report of a case and review of the literature.

A case of concomitant granuloma annulare (GA) and necrobiosis lipoidica (NL) is presented. The etiology of these two disorders remains obscure. The similarity of the histopathology in GA and NL might suggest a common origin. However, a review of the 5 previous cases of concomitant GA and NL and recent biochemical, immunological and immunohistochemical studies comparing GA to NL indicates an independent etiology for these two histologically related disorders. Some evidence points toward a closer relationship of NL with diabetes than GA, while GA may be related to delayed-type hypersensitivity reactions.