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: ENT
Most common cause of unilateral parotid swelling in a 27yr old male is: 
Select and explain. 
A. Wahin's tumor, B. Pleomorphic adenoma, C. Adenocarcinoma, D. Hemangioma
B: Pleomorphic adenoma
Answer: B: Pleomorphic adenoma 
Explanation: Pleomorphic adenoma or benign mixed tumor accounts for 80% of parotid tumors and 60% of all salivary gland tumors. Most common site is parotid gland though it can arise from submandibular gland, salivary gland of palate upper lip and buccal mucosa. Wahin's tumor occurs most common in males, but most common tumor in males still is pleomorphic adenoma.