title: Implications of oncocytic change in papillary thyroid cancer.
abstract: OBJECTIVE
  Although the presence of oncocytic change in less than 75% of a tumour is not considered to indicate oncocytic variants of papillary thyroid carcinoma (PTC), we frequently observe partial oncocytic change, especially in obese PTC patients. Thus, we sought to investigate the relationship between the presence of oncocytic change of PTC and its prognosis.
  
  
  METHODS
  We retrospectively studied 142 patients with PTC who had undergone surgery between 2000 and 2005, and re-evaluated their PTC slides to record the proportion of oncocytic change in 10% increments from 0% to 100%.
  
  
  METHODS
  We analysed the relationship between the proportion of oncocytic change and clinicopathological prognostic factors.
  
  
  RESULTS
  Oncocytic change was found in 45·8% (65/142) of PTC patients. The proportion of patients with oncocytic change was higher in obese patients than in lean patients and showed a significant correlation with the BMI (r = 0·195, P = 0·020). The PTC patients with oncocytic change showed a higher recurrence rate than PTC patients without oncocytic change (30·8% vs 11·7%, respectively; P = 0·005). The presence of oncocytic change in PTC patients was associated with a shorter disease-free survival in a Kaplan-Meier analysis after a mean follow-up of 8·9 years.
  
  
  CONCLUSIONS
  The patients with PTC with oncocytic change presented with a higher recurrence rate and were more likely to be obese. These findings suggest that presence of oncocytic change is a poor prognostic factor in PTC patients, even if the oncocytic change involves less than 75% of a tumour.
authors.affiliation: Department of Internal Medicine, Eulji University Hospital, Daejeon, Korea.
authors.forename: Jun Hwa
authors.initials: JH
authors.lastname: Hong
authors.affiliation: Research Centre for Endocrine and Metabolic Diseases, Chungnam National University School of Medicine, Daejeon, Korea.
authors.forename: Hyon-Seung
authors.initials: HS
authors.lastname: Yi
authors.affiliation: Department of Medical Science, Chungnam National University School of Medicine, Daejeon, Korea.
authors.forename: Shinae
authors.initials: S
authors.lastname: Yi
authors.affiliation: Department of Medical Science, Chungnam National University School of Medicine, Daejeon, Korea.
authors.forename: Hyeon-Woo
authors.initials: HW
authors.lastname: Kim
authors.affiliation: Department of Pathology, Daejeon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Daejeon, Korea. junguee@catholic.ac.kr.
authors.forename: Junguee
authors.initials: J
authors.lastname: Lee
authors.affiliation: Research Centre for Endocrine and Metabolic Diseases, Chungnam National University School of Medicine, Daejeon, Korea. kunsunkim@cnuh.co.kr.
authors.forename: Koon Soon
authors.initials: KS
authors.lastname: Kim
mesh_terms: D000328:Adult; D002277:Carcinoma / Q000401:mortality / Q000473:pathology*; D002291:Carcinoma, Papillary; D002452:Cell Count; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity; D024862:Oxyphil Cells / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000401:mortality / Q000473:pathology*