This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': "What is a Marjolin's ulcer? \nSelect and explain. \nA. It is a trophic ulcer, B. Meleney's gangrene, C. Malignant ulcer found on infected foot, D. Malignant ulcer found on the scar of burn", 'role': 'user'}, {'content': "Answer: D \nExplanation: Marjolin's ulcer is a malignant ulcer found on the scar of burns. It is also used to describe carcinomatous change occurring at the edge of a chronic venous ulcer. Chronic ulceration of old burn scars was noted by Marjolin to lead frequently to malignant degeneration. Most common type of cancer associated with it is squamous cell carcinoma, basal cell carcinomas can occur occasionally. Approximately 30 percent of burn scar carcinomas occur in the head and neck. They may metastasize aggressively. Treatment involves wide excision, but prophylactic regional node dissection has not improved moality. Adjuvant radiotherapy was found to improve survival. Ref: Schwaz's Principles of Surgery, 9th Edition, Chapter 9; Applied Basic Science for Basic Surgical Training By Andrew T. Raftery, Page 49.", 'role': 'assistant'}]