Objective: To investigate the clinicopathological features

diagnosis

and differential diagnosis of mucoepidermoid carcinoma arising in Warthin’s tumor of the parotid gland. Methods: The histological features and immunophenotype features of a patient with mucoepidermoid carcinoma arising in Warthin’s tumor of the parotid gland were analyzed

and the relevant literature was reviewed and summarized. Results: The female patient

aged 77 years

was found to have a painless mass in the right parotid gland for more than ten months. Microscopic examination showed a transition zone between Warthin’s tumor and mucoepidermoid carcinoma

and the carcinoma manifested as low-grade mucoepidermoid carcinoma. Bistratified cells of Warthin’s tumor were positive for CK5/6

luminal cells of Warthin’s tumor were positive for CK7

and the basal cells of Warthin’s tumor were positive for HCK and p63. The epidermoid cells of mucoepidermoid carcinoma were positive for CK5/6

and the mucous cells of mucoepidermoid carcinoma were positive for CK7

CEA

and PAS staining. Conclusion: Mucoepidermoid carcinoma arising in Warthin’s tumor is extremely rare and thus difficult to diagnose; particularly in freezing diagnosis

the key to diagnosis is to clarify the transition zone between Warthin’s tumor and mucoepidermoid carcinoma.