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: Pathology
Which of the following head and neck tumor has worst prognosis? 
Select and explain. 
A. Adenoid cystic carcinoma, B. Acinic cell carcinoma, C. Cystadenolymphoma, D. Mucoepidermoid carcinoma
A: Adenoid cystic carcinoma
Answer: A: Adenoid cystic carcinoma 
Explanation: Ans. is 'a' i.e., Adenoid cystic carcinoma "Adenoid cystic carcinoma has been described as one of the most biologically aggressive and destructive malignant neoplasms, presenting a tendency for local recurrance and late distant metastasis throughout the course of disease." o The adenoid cystic carcinoma, adenocarcinoma, squamous cell carcinoma and undifferentiated carcinoma are all agggressive malignant tumors that carry a poor prognosis regardless of treatment. o The acinic cell carcinoma and the mucoepidermoid carcinoma, although undoubtedly malignant tumors with a potential for local invasion and metastatic spread, are frequently very low grade histologically and do not require the radical treatment needed for more aggressive tumors. o Cysadenolymphoma (Wahin's tumor) is a benign tumor.