Evaluation of Adenoid cystic carcinoma and polymorphous low-grade adenocarcinoma by immunohistochemistry

Salivary gland tumors classification continuously undergoes alternations, especially in the recent years. This study used immunohistochemical markers for distinguishing between polymorphous low-grade adenocarcinoma (PLGA) and adenocarcinoma carcinoma (AdCC) which have several overlapping histological and clinical features. Ten AdCC and eight PLGA with five normal minor salivary glands were selected after review by two oral pathologists. LSAB method was used for seven markers: carcinoembryonic antigen, epithelial membrane antigen, muscle specific actin, vimentin, S100, P53 and Ki-67. Finally, the data were analyzed by Mann-Whiteny test. Analysis of data showed a high expression of CEA, EMA and Ki-67 in AdCC compared to PLGA. Although, CEA (P<0.001) expression was limited to luminal cells. In contrast, MSA (P=0.034) expression in nonluminal cells, and Ki-67 (P<0.001) occurred in both luminal and nonluminal cells. Also there was highly expression of vimentin and S-100 in PLGA with no significancy for EMA and Tp53. The result of this study suggests that ICH can be a helpful tool. The immunostaining of AdCC and PLGA with CEA, Vimentin and Ki-67 were of greater significant, S100 and MSA were less significant and the others (EMA and P53) could not offer an adjunctive aid in differential diagnosis between the two tumors.