Synchronous multiple unilateral parotid gland tumors of benign and malignant histological types: case report and literature review ?

摘要

Salivary gland tumors are a very heterogeneous group oflesions. According to the histological classification publishedby WHO in 2005, 10 types of benign and 24 types of malignant tumors of the salivary glands can be distinguished. Allof these lesions are relatively rare, and represent only 3---4%of head and neck tumors. 80% of them are located within theparotid gland, and they usually present as a single parotidlesion.1 Unilateral parotid neoplasms are very uncommon,and they usually have the same histological type. The mostcommon type of such a lesion is Warthin tumor (6---12% of alladenolymphomas).2 The coexistence of tumors of differenthistological types in the same parotid gland constitutes lessthan 0.3% of all salivary gland neoplasms.3 The most commonhistological combination is Warthin tumor and pleomorphicadenoma. Two different unilateral parotid neoplasms can bemetachronous or synchronous. However, even when morethan one tumor occur at the same time, they must be distinguished from hybrid tumors, in which we can find twoor more distinct histological types of neoplasms having anidentical origin in the same tissue.4Synchronous benign and malignant ipsilateral parotidtumors are an extremely rare phenomenon. It was describedfor the first time by Tanaka in 1953 as mucoepidermoid carcinoma associated with Warthin tumor.5 To our knowledgeno case in the literature mentioned the occurrence of atumor consisting of carcinoma ex pleomorphic adenoma andWarthin tumor, which is reported in the present paper.