[Cervical lymph node metastasis in adenoid cystic carcinoma of the salivary glands: A clinicopathologic study].

objectiveTo investigate the incidence and clinicopathologic features of cervical lymph node metastasis in salivary gland adenoid cystic carcinoma (AdCC).

methodsRetrospective analysis was made in 798 AdCC patients who underwent tumor resection during January, 2001 to January, 2019 in Peking University School and Hospital of Stomatology, especially the clincopathologic characteristics of 82 cases with lymph node metastasis.

resultsIn the study, 82 of the 798 patients were identified with cervical lymph node metastasis, which was confirmed by histopathological examination. The palate, the region of sublingual gland and mouth floor, and the parotid were the frequently involved primary sites for AdCCs. The general incidence rate of lymph node metastasis was approximately 10%. The submandibular gland, the region of sublingual gland and mouth floor, and the mobile tongue were the most frequent sites of lymph node metastasis with the incidence rates of 20.8%, 16.1%, and 15.1%, respectively; while lymph node metastasis was uncommon in the tumors which were the origin from the palate and parotid, with incidence rates of 6.1% and 3.4%, respectively. Most AdCC cases (70.7%) showed the classic "tunnel-style" metastatic pattern of occurrence, and the level I and II regions were the most frequently involved areas. The 5-year and 10-year overall survival rates of the patients with lymph node metastasis were 77.4% and 20.6% respectively, while the 5-year and 10-year overall survival rates of the patients with no lymph node metastasis were 83.5% and 57.6%, respectively. The univariate analysis demonstrated that statistically significant differences in the overall survival for the presence of lymph node metastasis (P<0.001). In the meantime, the 5-year disease-free survival rate of the patients with lymph node metastasis also showed statistically significant differences to that of the AdCC patients with no lymph node metastasis. In addition, the primary site and histological grade were significantly associated with lymph node metastasis, and the high-grade solid growth pattern was identified as a strong predictor for the occurrence of lymph node metastasis.

conclusionCervical lymph node metastasis has a high tendency of occurrence in submandibular gland and tongue-mouth floor complex, and the high-grade solid growth pattern could be taken as a strong predictor for the occurrence of lymph node metastasis, which correlates to poor prognosis of AdCC patients. A selective neck dissection should be considered as a management in such patients.