Multiple primary parotid gland tumors are rare, accounting for 1.7-5% of all parotid neoplasms, and the occurrence of bilateral parotid gland tumors is even lower (1.3-3.5%). These tumors can be synchronous or metachronous and the most common histologic type of bilateral parotid gland tumors is Warthin tumor (79.2-90%). Combined benign and malignant lesions and bilateral neoplasms of
different histologic types are even less frequently found.