Myoepithelioma.

Myoepithelial cells are integral components of normal salivary glands. Their active or passive participation in the histogenesis of several salivary gland tumors is a debated issue. This debate notwithstanding, a rare form of salivary tumor composed entirely of myoepithelial cells exists and probably represents a monomorphic form of mixed tumor. This tumor, the myoepithelioma, occurs in most major and minor salivary tissues and is generally a biologically benign lesion.