A Case of Pleomorphic Adenoma Arising from Accessory Parotid Gland.

Although accessory parotid glands are found in 20-70% of normal persons, tumors arising from accessory parotid glands are reportedly rare. We demonstrated a case of pleomorphic adenoma arising from the accessory parotid gland. A 43-year-old female was brought to our hospital with a left cheek mass. Imaging demonstrated an oval-shaped tumor on the masseter muscle located in the mid-portion of her cheek, without any evidence of relationship with the parotid gland. Surgically the tumor was completely removed through a transparotid approach and pathologically diagnosed as pleomorphic adenoma.Reports of the incidence of accessory parotid glands in humans are inconsistent, so we investigated the various reported values. We concluded that over 55% of normal people have accessory parotid glands in their left or right cheeks.