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61 year old male with facial pain and right parotid mass.
Adenoid cystic carcinoma (ACC) accounts for about 10% of salivary gland carcinomas. It most frequently occurs in the major salivary glands but has been reported in the oral cavity, sinonasal tract and rarely, other sites. It typically presents as a slow-growing mass with numbness, paraesthesia or pain due to its propensity for neural invasion. It is generally indolent but long-term prognosis is poor as it is associated with a protracted course of multiple recurrences and metastases.
ACC is a malignancy composed of epithelial and myoepithelial neoplastic cells. Most commonly, it exhibits a cribiform growth pattern (as in this case) with sharp punch-out spaces filled with basophilic matrix of tumor cell nests. However, it can also exhibit tubular and solid growth patterns. Perineural invasion is usually conspicuous. MYB fusion, including MYB-NFIB translocation is found in greater than 80% of ACCs.