Metastasizing pleomorphic adenoma of parotid gland: Case report.

Pleomorphic adenoma is a benign tumor and the most common salivary gland neoplasm. Metastasizing pleomorphic adenoma shares histological characteristics with pleomorphic adenoma but exhibits malignant behavior, including local lymph node involvement and/or distant metastasis. Several potential risk factors for metastasizing pleomorphic adenoma have been identified, some of which are associated with incomplete tumor clearance due to inadequate surgical techniques used in the treatment of primary pleomorphic adenoma. Here, we present a rare case of metastasizing pleomorphic adenoma originating from the parotid gland and describe its clinical features. The patient was a 75-year-old female with a surgical history of enucleation of a pleomorphic adenoma in the left parotid gland. Total parotidectomy and left neck dissection were performed for the left parotid tumor this time, and the patient attended one postoperative outpatient visit but subsequently was lost to follow-up.