Adenoid Cystic Carcinoma of the Buccal Mucosa with Rare Delayed Frontal Bone Metastasis: A Case Report

Adenoid cystic carcinoma (AdCC) is a malignant neoplasm, which accounts for 5-10% of all salivary gland tumors (1). About 50% of these tumors originate from intraoral minor salivary glands usually in the hard palate (1). Three clinically obvious characteristics of AdCC include slow growth rate, perineural invasion and high incidence of distant metastasis (1). The most commonly-affected sites of distant metastasis are bone, liver and brain, followed by lungs (2). Lymph node metastases are rare;  The most common sites  involved by hematogenous spread are lungs (2).  This is a report about a patient with a rare form of AdCC on buccal mucosa with an unusual metastasis to the frontal region after a two-year follow up.