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': 'Mucoepidermoid carcinoma arises form - \nSelect and explain. \nA. Myothelium, B. Epithelium, C. Acinus, D. Mucin secreting and epidermal cells', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Mucoepidermoid carcinomas are composed of variable mixtures of squamous cells, mucus-secreting cells, and intermediate cells.\n"The low-grade mucoepidermoid carcinoma is composed of largely mucin-secreting cells, whereas in high-grade tumors, the epidermoid cells predominate."- Schwartz\nThey are the most common malignant tumors of the salivary glands.\n\nTreatment\n\nThe primary t/t of all salivary malignancy is surgical excision:\n\nfor parotid malignancies-\n\nSuperficial parotidectomy with preservation of CN VII.\nTotal parotidectomy with nerve preservation if deep lobe is involved.\n\nfor other salivary gland -\n\nEnbloc removal of the involved gland\nNeck dissection for lymph nodes is done\nclinically palpable nodes\nfor high grade malignancies\nRadiation therapy is used postoperatively for specific indications\nhigh grade histology\npresence of extraglandular disease\nperineural invasion\ndirect invasion of regional structure\n\tregional metastasis', 'role': 'assistant'}]