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: Ophthalmology
[{'content': 'Which of the following is the MOST common tumour of lower eyelid? \nSelect and explain. \nA. Sebaceous Ca, B. BCC, C. SCC, D. Malignant melanoma', 'role': 'user'}, {'content': "Answer: B \nExplanation: Basal cell carcinoma (BCC) arises from pluripotent stem cells within the basal layers of the epidermis and external root sheaths of hair follicles. It comprises about 90% of all eyelid malignancies. The incidence of basal cell carcinoma of the eyelid skin increases with age and there is a slight male preponderance. Clinically, it typically manifests as a firm painless indurated nodule with a pearly, rolled border and fine (small) telangiectatic surface vessels. 65% of cases occur in the lower eyelid. Treatment consists of complete surgical excision. Ref: Vagefi M., Sullivan J.H., Correa Z.M., Augsburger J.J. (2011). Chapter 4. Lids & Lacrimal Apparatus. In P. Riordan-Eva, E.T. Cunningham, Jr. (Eds), Vaughan & Asbury's General Ophthalmology, 18e.", 'role': 'assistant'}]