Nonsebaceous lymphadenoma in the parotid gland: true neoplastic or reactive? A report of two cases.

We report 2 rare cases of nonsebaceous lymphadenoma (NSL) in the parotid gland. In both cases, microscopic examination revealed central dilated duct-like structure and its surrounding many cysts in the background of the lymphoid stroma. The cysts were lined with luminal cells and abluminal cells, with the latter being predominant. Occasionally, foci of abluminal epithelial islands were observed. Immunohistochemical findings showed that these tumors had basal cell phenotypes and could support the diagnosis of NSL. The microscopic architectural pattern indicated a cystic dilated duct-glands unit and metaplasia or hyperplasia of abluminal cells. We wondered whether these NSLs were true neoplasia or an indication of a nonneoplastic reactive process. Further investigation of molecular studies of large series in, for example, the clonal or chromosomal state, would be necessary to clarify this point.