It has been demonstrated in salivary and lacrimal gland pleomorphic adenomas that the longer the tumor is present, the greater the likelihood of malignancy, with a malignancy rate of less than 3% within 10 years and 10%-20% beyond 20 years. It is important to distinguish between restrictive or non-invasive carcinoma of pleomorphic adenoma and non-restrictive or invasive carcinoma of pleomorphic adenoma. Cases of restrictive carcinoma are mainly benign pleomorphic adenomas with localized regional malignancy. From a clinical perspective, they have the typical signs/symptoms and imaging manifestations of pleomorphic adenoma, but with localized areas of microscopic evidence of malignancy histology, such as mitosis, malignant gland formation, or atypical cell proliferation without protrusion into adjacent tissue. Interstitial differentiation is usually adenocarcinoma, but rarely it can also be classified as adenoid cystic carcinoma, squamous carcinoma or sarcomatoid change. Treatment: Surgery is the same as for benign pleomorphic adenoma.