This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Surgery
Which parotid tumor spreads along nerve sheath ? 
Select and explain. 
A. Pleomorphic adenoma, B. Mucoepidermoid carcinoma, C. Adenoid cystic carcinoma, D. Wahin's tumor
C: Adenoid cystic carcinoma
Answer: C: Adenoid cystic carcinoma 
Explanation: Adenoid cystic carcinoma has got high affinity for perineural spread(both axially and circumferentially;antegrade and retrograde fashion) along mandibular and maxillary divisions of trigeminal (common) and facial nerve .It infiltrates nerve more proximally for long distance. Tumor may reach Gasserian trigeminal ganglion ,pterygopalatine ganglion and cavernous sinus SRB,5th,417 .