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Adenoid cystic carcinoma of the parotid with facial nerve invasion.

BACKGROUND
Adenoid cystic carcinoma comprises approximately 10% of all epithelial salivary neoplasms and most frequently involves the parotid. Perineural invasion is a common feature but intraneural invasion and spread is less common.


AIM
The authors report a case of parotid adenoid cystic carcinoma with invasion and spread via the facial nerve with an emphasis on radiologic features.


OBSERVATION
We report a case of a 47-year-old man presenting with a right submandibular mass evolving for 4 years. On physical examination, the mass was firm painless, well delineated. There was no facial paralysis. The magnetic resonance imaging (MRI) examination showed a right parotid gland solid mass located in the deep lobe of the parotid gland with mastoid bony involvement.The mass was heterogenously enhanced. High resolution non contrast computed tomographie (CT) scan of the temporal bone showed in the axial and coronal cuts, a widening of the mastoid segment of the facial canal with involvement of the facial nerve. Pathologic examination of the resected specimen revealed histological features of adenoid cystic carcinoma with intra neural invasion of the mastoid segment of the facial nerve. The surgical margins were free. The evolution was favourable 5 years later.


CONCLUSION
This study confirms that multiplanar approach of MRI allows rapid detection of adenoid cystic carcinoma. The influence of intraneural invasion and spread on survival remains controversial.