Differential diagnosis of lymphoepithelial lesions of salivary glands. With particular reference to characteristic duct lesions

Several salivary gland diseases present with the histomorphological feature s of a lymphoepithelial lesion with or without cyst formation. Some of the most important differential diagnoses (Sjogren's syndrome, marginal zone B- cell lymphoma, HIV-associated cystic lymphoepithelial lesion) are systemic diseases and require further investigation and therapy. However, in small b iopsy specimens and in cases without relevant clinical information an exact diagnosis may be difficult to obtain. We have recently determined that the characteristic lymphoepithelial duct lesions develop by proliferation of b asal cells of striated ducts, while we could not confirm the previously pos tulated participation of myoepithelial cells ("epimyoepithelial lesion/sial adenitis"). Although these duct lesions are typical of Sjogren's syndrome, they manifest in several diseases of salivary glands, exhibiting characteri stic patterns concerning frequency and localization. This review discusses the most important lymphoepithelial diseases of salivary glands with respec t to clinical presentation and histomorphology. Particular emphasis is plac ed on the lymphoepithelial duct lesions.