HIV-unrelated benign lymphoepithelial cyst of the parotid glands containing lymphoepithelial lesion--like structures: a report of 3 cases.

Benign lymphoepithelial cyst (BLC) of the salivary gland is uncommon. Among report of these lesions, there were no previous cases of lymphoepithelial lesion (LeL) in human immunodeficiency virus type-1 (HIV-1) unrelated BLC. This study reports 3 cases of HIV-unrelated BLC containing LeL-like structures. Pathologically, 3 lesions were characterized by cuboidal epithelial-lined, cystic spaces, numerous lymphoid follicles, and dense lymphoplasmacytoid infiltrate. Moreover, small lymphocytes invaded the epithelial clusters forming LeL-like structures. Histological findings of 3 lesions resembled marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type. However, staining with CD3, CD5, and CD20 demonstrated the mixed nature of small lymphocytes invading the epithelial clusters (LeLlike structures). Moreover, there were no CD43+ B-lymphocytes in any of the cases. The polytypic nature of B-lymphocytes was demonstrated by immunohistochemistry and polymerase chain reaction. The 3 cases indicate that HIV-unrelated BLC should be added to the differential diagnosis of MALT-type lymphoma involving the parotid glands.