Squamous cell carcinoma arising in long-standing necrobiosis lipoidica.

Necrobiosis lipoidica (NL) is a disease of collagen. Squamous cell carcinomas developing in areas of chronic ulceration and scarring have been well documented in a variety of skin diseases but rarely in areas of necrobiosis lipoidica. The case history of a 76-year-old female is presented, whose squamous cell carcinoma appeared 30 years after the diagnosis of necrobiosis lipoidica. The clinical and histopathological picture is described, stressing the importance of the unusual association of the two pathologies in the prognostic.