Squamous cell carcinoma arising in an area of long-standing necrobiosis lipoidica

Background: Squamous cell carcinoma in an area of chronic ulceration is a well-documented phenomenon. However, its occurrence arising de novo in an area of necrobiosis lipoidica is rare. Method: We report a case in a 53-year-old female who presented with a 2 month history of an erythematous nodule occurring in a plaque of necrobiosis lipoidica on the medical aspect of the right lower leg. She had a background of poorly controlled Type 1 diabetes. Results: Histopathological findings revealed a well-differentiated squamous cell carcinoma overlying an area of necrobiosis lipoidica. Treatment was by excision and split-thickness skin graft. Conclusion: Clinicians should be aware of malignant transformation within a plaque of necrobiosis lipoidica. Early detection will allow conservative treatment.