All are true about pleomorphic adenoma except:-

Risk of malignant transformation is low (3-5%) in pleomorphic adenoma. Malignant mixed tumors include cancers originating from pleomorphic adenomas, termed carcinoma ex pleomorphic adenoma, and de novo malignant mixed tumors. The risk for malignant transformation of benign pleomorphic adenomas is 1.5% within the first 5 years, but risk increases to 9.5% when the benign tumor has been present for more than 15 years.