This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Surgery
[{'content': 'An elderly woman underwent a radical mastectomy with radiation to the axilla 20 years ago. For 25 years, she has had an open wound that has never healed. It is not a recurrence of breast cancer. It is most likely: \nSelect and explain. \nA. Basal cell carcinoma, B. Squamous cell carcinoma, C. Hypertrophic granulation tissue, D. Malignant melanoma', 'role': 'user'}, {'content': "Answer: B \nExplanation: First described by Marjolin in 1828 and known as Marjolin's ulcers, malignant degeneration arising in a chronic wound is nearly always squamous cell carcinoma. These lesions are most commonly seen in burn scars but have been associated with osteomyelitis, radiation therapy, hidradenitis suppurativa, and diabetic ulcers.", 'role': 'assistant'}]