
Adenoid Cystic Carcinoma (ACC) is a relatively rare tumor that accounts for 1% of all head and neck malignancies and 10% of all salivary neoplasms, according to the World Health Organization (WHO) classification of head and neck tumors. Most ACCs originate from the major and minor salivary glands, and a minority called salivary gland–type carcinomas, arise from glands in the nasal, paranasal, and external spaces. ACC has classically been described as having an indolent but persistent and recurrent course, with the delayed onset of distant metastases and eventual death of affected patients. Therefore, although uncommon, ACC is one of the most aggressive of the salivary gland tumors.