Carcinoma Expleomorphic Adenoma, Carcinosarcoma, Metastasizing Mixed Tumor

Epidemiology

Carcinoma ex-pleomorphic adenoma (CEPA) is an epithelial malignancy that is thought to arise from a preexisting pleomorphic adenoma. These lesions are believed to represent malignant degeneration of a pleomorphic adenoma. Some estimates suggest that nearly 25% of all pleomorphic adenomas may undergo malignant change if left untreated. CEPA may also occur in the setting of multiple recurrent pleomorphic adenomas. CEPA constitutes between 7 and 17% of all parotid malignancies and represents 2 to 5% of all salivary gland tumors. Other sites of occurrence include the submandibular gland, the palate, lip, paranasal sinuses, nasopharynx, tonsil, and minor salivary glands of the palate.

CEPA should be differentiated from other malignancies associated with pleomorphic adenomas. Carcinosarcoma is a true malignant pleomorphic adenoma with malignant epithelial and stromal elements. Metastasizing mixed tumor is the rarest of the malignancies associated with pleomorphic adenomas. These latter lesions are thought to arise from multiple procedures that have allowed cells to enter the lymphatic and venous system.

Clinical Findings

Patients usually present between the sixth and seventh decades of life. Patients usually complain of a mass that has often been present for 10 to 15 years which has suddenly increased in size. Patients may also present with pain and facial nerve palsy.

Pathology

The gross appearance of CEPA is a firm nodular mass that is partially encapsulated or unencapsulated. The lesions may occasionally be cystic and contain central hemorrhage or necrosis.