Carcinoma ex pleomorphic adenoma is a high-grade salivary gland cancer in which malignant transformation occurs in a previously benign pleomorphic adenoma. A 56-year-old woman attended the Hospital Dental Center presenting an exophytic sessile nodule on the hard palate. She had been diagnosed with a pleomorphic adenoma in this region a year prior. Computed tomography revealed a hypodense image in the left region of the hard palate. Microscopic examination demonstrated a neoplasm composed of epithelial and myoepithelial cells, organized in ductal structures, cords, and nests. Islands with epithelial cells, presenting nuclear pleomorphism, clear cells, and cystic spaces bounded by mucous cells characterized the malignant component. Keratin pearls were also present in the center of some islands. The specimen's margins were compromised. A final diagnosis of carcinoma ex pleomorphic adenoma was obtained. The patient was referred for removal of surgical margins and remains to undergo clinical follow-up.