Imaging and clinical features of nasopharyngeal adenoid cystic carcinoma

Objective To analyze the spreading patterns nasopharyngeal carcinoma and nasopharyngeal adenoid cystic carcinoma.Methods Eighteen pathologically confirmed consecutive cases of adenoid cystic carcinomas （ACC）and 182 cases of untreated nasopharyngeal carcinomas （NPC） were reviewed.Results Compared with NPC,ACC had higher rates of T4 disease （14.3% vs 38.9%,x^2 =7.197,P =0.007） and paralyzed cranial nerve（6.0% vs 38.9%,x^2 =37.936,P 〈 0.001）.There was no significant difference in skull base invasion rates between 2 groups （53.3% vs 66.7%,x^2 =1.181,P =0.277）.ACC had higher rates of MRI-detected cranial nerve canal invasion （32.4% vs 55.6%,x^2 =3.881,P =0.049） and cavernous sinus invasion （13.7% vs 33.3%,x^2 =7.710,P =0.028） than NPC.Lymph node metastasis occurred in 64.8% of ACC,and 11.1% of NPC （x^2 =19.699,P〈 0.001）.Conclusion ACC has a higher rate of cranial nerve invasion and NPC has a higher rate of lymphatic metastasis. Key words: Nasopharyngeal neoplasms;  Carcinoma, adenoid cystic;  Magnetic resonanceimaging