title: Papillary thyroid microcarcinomas located at the middle part of the middle third of the thyroid gland correlates with the presence of neck metastasis.
abstract: BACKGROUND
  Papillary thyroid microcarcinomas (PTMCs), located at upper poles of the thyroid, are associated with lateral neck metastasis (LNM) according to previous reports. Controversy remains regarding the correlation between the location of PTMCs and central neck metastasis (CNM).
  
  
  METHODS
  Medical records of 949 patients with PTMCs diagnosed between 2010 and 2013 were reviewed retrospectively. With a subdivision of the middle third of the thyroid gland, correlations between tumor location and CNM/LNM along with other clinicopathologic factors were analyzed by binary logistic regression.
  
  
  RESULTS
  PTMCs located in the middle part of the middle third of the thyroid gland (MPMT) showed the greatest rate of CNM (57.5%) among all locations. PTMCs located at isthmus showed the second greatest rate of CNM (44.3%). In the multivariate analysis, MPMT, tumor size >0.5 cm, young and middle age, male sex, multifocality within the affected lobe, and capsular invasion were correlated with CNM. PTMCs located at upper poles and MPMT showed comparatively high rates of LNM (8.6% and 8.3%). Consistent with previous reports, an upper pole location, MPMT, and a tumor size >0.5 cm greatly correlated with LNM in the multivariate analysis. Eleven patients had skip metastases, which only occurred with upper/lower pole locations and MPMT.
  
  
  CONCLUSIONS
  PTMCs located in the MPMT correlated with both CNM and LNM. Tumor location along with other clinicopathologic factors such as young and middle age, male sex, and tumor size >0.5 cm could facilitate preoperative stratification and guide operative management for patients with PTMC.
authors.affiliation: Department of General Surgery, Second Affiliated Hospital School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Dapeng
authors.initials: D
authors.lastname: Xiang
authors.affiliation: Department of Molecular and Cellular Biology, UC Berkeley, Berkeley, CA.
authors.forename: Liangqi
authors.initials: L
authors.lastname: Xie
authors.affiliation: Department of General Surgery, Second Affiliated Hospital School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Yuanliang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of General Surgery, Second Affiliated Hospital School of Medicine, Zhejiang University, Hangzhou, China. Electronic address: pkudaniel@gmail.com.
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Ultrasonography, Second Affiliated Hospital School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Yurong
authors.initials: Y
authors.lastname: Hong
authors.affiliation: Department of General Surgery, Second Affiliated Hospital School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000473:pathology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009333:Neck; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000473:pathology*