This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Salivary Gland Neoplasms, Subject name: Surgery
[{'content': 'Which among the following parotid tumor spreads through neural sheath : \nSelect and explain. \nA. Mixed parolid tumor, B. Adenocystic Ca, C. Sq. Cell Ca, D. Oxyphillic lymphoma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans is \'b\' ie Adenocystic Ca "Adenoid cystic carcinoma, which has a propensity for neural invasion, is the second most common malignancy in adults. Skip lesions along nerves are common and can lead to treatment failures because of the difficulty in treating the full extent of invasion. Adenoid cystic carcinomas have a high incidence of distant metastasis, but display indolent growth. It is not uncommon for patients to experience lengthy survival despite the presence of disseminated disease." - Schwartz 8/e "Treatment consists of removal of gross tumor with radiation therapy for the microscopic disease that is assumed to exist at the periphery of the tumor. Sabiston 18/e p836', 'role': 'assistant'}]