Polymorphous low-grade adenocarcinoma (PLGA) is a minor salivary gland neoplasm usually arising intraorally, primarily in the palate.It is characterized by morphologic variability, cytologic uniformity, and an infiltrating growth pattern.Recently, PLGA is listed in the existing WHO classification (1990) as a subclassification of adenocarcinomas. We present an unusual case of PLGA involving the upper lip of a 50-year-old male. The histopathologic findings are, in contrast to weaker atypism of tumor cells, considerable histologic variety.The spectrum of growth patterns included solid, clear-cell, adenoid cystic, and fascicular areas.Tumor cells were isomorphic with a lightly eosinophilic cytoplasm and uniformed round nuclei with a few mitoses. Immunohistochemically, tumor cells were stained with S-100 protein, carcinoembryonic antigen (CEA), cytokeratin (KL-1), vimentin, epithelial membrane antigen (EMA), and glial fibrillary acidic protein (GFAP).
