Head and Neck Tumors - Adenoid Cystic Carcinoma

Adenoid cystic carcinoma (ACC) has bi-directional differentiation of ductal epithelium and myoepithelium, and is mainly distinguished from pleomorphic adenomas, basal cell adenomas and adenocarcinomas, epithelial-myoepithelial carcinomas, and pleomorphic, low-grade, malignant adenocarcinomas. A specific MYB-NFIB fusion gene abnormality is seen in approximately 50% of adenoid cystic carcinomas, and is not seen in other salivary or non-salivary tumors.Abnormal expression of the MYB protein is commonly seen in adenoid cystic carcinomas (approximately 80%) but is less specific (approximately 14% are also expressed in non-salivary tumors).The MYB/NFIB fusion gene is seen in 30-50% of adenoid cystic carcinomas and can be used to differentiate adenoid cystic carcinomas from adenomatous cystic carcinomas. The MYB/NFIB fusion gene is found in 30%-50% of adenoid cystic carcinomas and can be used as an aid in the diagnosis of adenoid cystic carcinomas.