Head and Neck Tumors - Adenoid Cystic Carcinoma

Adenoid cystic carcinoma (ACC) has bi-directional differentiation between 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; this fusion gene abnormality has not been seen in other salivary or non-salivary tumors.MYB protein expression is common in adenoid cystic carcinomas (approximately 80%) but 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. It can be used as an aid in the diagnosis of adenoid cystic carcinoma.