Molecular pathology of adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is a slow-growing but locally aggressive salivary gland tumor. ACC is composed of ductal/tubular epithelial cells and basal/myoepithelial cells, which form cribriform, tubular, and solid growth patterns in variable combinations and dominance. ACC from different anatomic sites have similar morphological, molecular, and genetic changes. The key molecular alteration in ACC is chromosomal fusion/rearrangement/translocation involving MYB or MYBL1, usually with NFIB as a fusion partner. In this review, we summarize the pathology and molecular alterations in ACC and their clinical significance.