title: Occult contralateral carcinoma in patients with unilateral papillary thyroid microcarcinoma.
abstract: BACKGROUND
  The optimal resection extent for papillary thyroid microcarcinoma (PTMC) confined within a unilateral lobe remains controversial.
  
  
  METHODS
  We reviewed the medical records of 132 consecutive patients who underwent total thyroidectomy for the treatment of clinically unilateral PTMC between March 2005 and March 2009. The frequency, pattern, and predictive factors for occult contralateral carcinoma in these patients were analyzed with respect to the following variables: age, gender, tumor size, multifocality of primary tumor, presence of perithyroidal invasion, lymphovascular invasion or capsular invasion, presence of central lymph node metastasis, and the presence of coexistent benign nodules in the contralateral lobe based on preoperative evaluation and final pathology.
  
  
  RESULTS
  A total of 22 patients (16.7%) had occult PTMC in the contralateral lobe. In multivariate analysis, multifocality of the primary tumor (P = 0.026, odds ratio = 7.714) and the presence of coexistent benign nodule in the contralateral lobe by preoperative evaluation (P = 0.036, odds ratio = 3.500) were independent predictive factors for occult contralateral PTMC presence. However, there were no significant differences between the presence of occult contralateral carcinomas and age, gender, tumor size, perithyroidal invasion, lymphovascular invasion, capsular invasion, central lymph node metastasis, and coexistent benign nodules by final pathology.
  
  
  CONCLUSIONS
  Based on our findings, total thyroidectomy, including the contralateral lobe, should be considered for the treatment of unilateral PTMC if it presents as a multifocal tumor in the unilateral lobe and/or if nodules are found in the contralateral lobe during preoperative evaluation.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Cancer Research Institute, Research Institute for Medical Sciences, Chungnam National University College of Medicine, Daejeon, Korea.
authors.forename: Bon Seok
authors.initials: BS
authors.lastname: Koo
authors.forename: Hyun Sil
authors.initials: HS
authors.lastname: Lim
authors.forename: Young Chang
authors.initials: YC
authors.lastname: Lim
authors.forename: Yeo-Hoon
authors.initials: YH
authors.lastname: Yoon
authors.forename: Yong Min
authors.initials: YM
authors.lastname: Kim
authors.forename: Yong Ho
authors.initials: YH
authors.lastname: Park
authors.forename: Ki-Sang
authors.initials: KS
authors.lastname: Rha
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002291:Carcinoma, Papillary / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy; D016896:Treatment Outcome