Adenoid cystic carcinoma of the oral cavity: immunohistochemical study of four cases.

Adenoid cystic carcinoma (ACC) in the oral cavity is rare, and no immunohistochemical studies of ACC in the oral cavity have been performed. This report describes the immunohistochemical study of four ACCs of the oral cavity. The male to female ratio was 1:3. The age was 43, 51, 59 and 64 years. The location was tongue (n=2), buccal mucosa (n=1), and gingiva (n=1). Histochemically, all ACCs were positive for neutral, carboxylated and sulfated mucins. Immunohistochemically, ACC was consistently positive for cytokeratin (CK) AE1/3, CK 34βE12, CK5/6, CK7, CK14, CK18, p63, CA19-9, c-KIT (CD117), PDGFRA, MUC1, and Ki-67 (labeling index: 5%, 15%, 20% and 40%). ACC was consistently negative for CK8, CK20, desmin, S100 protein, CD34, chromogranin, MUC2, MUC5AC and MUC6. Some ACCs were positive for CK CAM5.2 (3/4), CK19 (1/4), EMA (2/4), CEA (2/4), vimentin (3/4), α-smooth muscle actin (2/4), p53 (2/4), CD10 (2/4), and synaptophysin (1/4). These results may provide basic knowledge of ACC of the oral cavity.