Mucoepidermoid Carcinoma Superimposed on a Warthin's Tumor: A Case Report and Review of the Literature

INTRODUCTION: Warthin's tumor (WT) is the second most common neoplasm of the parotid gland and consists of two components, including lymphoid stroma and glandular epithelium. The malignant transformation of this tumor occurs most often in the lymphoid component; however, the carcinomatous transformation of the epithelial component is rare. CASE REPORT: We present a patient who had a mass in the right mandibular angle two years before referral. A cystic mass was reported on sonography, and the patient underwent superficial parotidectomy with a pre-operative impression of lymphangiomatouse-like lesions. In the microscopic view, the sections revealed salivary gland neoplastic lesion with the diagnosis of WT. On the periphery of the neoplasm, another neoplastic lesion was observed along with infiltrative borders and diagnosis of mucoepidermoid carcinoma. CONCLUSION: The WT is one of the most common tumors of the salivary glands. Malignancy transformation of the WT is a rare event. However, due to the importance of the treatment type, the surgeon should consider this issue in cystic lesions suspected of WT.