Lymphoepithelial cyst of the parotid gland--a case report.

The lymphoepithelial cyst has been commonly termed branchial cleft cyst or branchial cyst. Although many theories, including the branchial apparatus theory, thymic duct theory, and inclusion theory, have been put forward, the etiology is still controversial. Parotid lymphoepithelial cysts are rare and could be divided into two groups, AIDS-related and non-AIDS related, by the relationship with HIV infection. A non-AIDS related lymphoepithelial cyst of left parotid gland in an 81-year-old man presenting as a parotid tumor is described. A left partial parotidectomy was carried out to remove the lesion. There was no recurrence after 2 years. Lymphoepithelial cysts of the parotid gland are often misdiagnosed as other benign tumors in spite of detailed preoperative investigations. Thus a pathological proof is needed for precise diagnosis. In addition, we also need to take the possibility of HIV infection into consideration, although Taiwan is not an AIDS epidemic area.