title: Role of galectin-3 immunodetection in the cytological diagnosis of thyroid cystic papillary carcinoma.
abstract: OBJECTIVE
  Cystic thyroid lesions can harbour an occult papillary carcinoma, which fine needle aspiration (FNA) biopsy may fail to detect. Recently, new markers such as galectin-3 lectin have been proposed to distinguish benign from malignant thyroid lesions of follicular origin. The aim of this study was to assess the role of galectin-3 immunodetection in a series of FNA cytological samples of benign and malignant thyroid cystic nodules.
  
  
  METHODS
  We retrospectively analysed galectin-3 expression by immunoperoxidase staining on 32 cytological paraffin-embedded samples of cystic papillary carcinoma and on 12 samples of benign cysts, both obtained by FNA biopsy. Specificity, sensitivity, positive/negative predictive values, and accuracy of standard cytological examination and galectin-3 immunodetection were assessed.
  
  
  RESULTS
  Among cystic papillary carcinomas, 29 of 32 samples were galectin-3 positive, whereas standard FNA cytology made a correct diagnosis in only 25 of 32 samples. All the benign cysts were negative for galectin-3. In comparing the sensitivity and specificity of the two methods, it appeared that both had a 100% specificity, whereas the sensitivity of cytological examination alone was 75% versus 89.3% obtained by galectin-3 immunohistochemistry.
  
  
  CONCLUSIONS
  Galectin-3 immunostaining represents a valid pre-operative adjunct to pick up malignant cells in those cases where a very poor number of epithelial cells may lead to a cytological misdiagnosis. Therefore, we suggest that in poorly cellular FNA biopsies of simple or complex thyroid cysts, galectin-3 expression by epithelial cells is consistent with a cystic carcinoma and supports surgical treatment indication.
authors.affiliation: Department of Pathology, University of Turin, Italy. mauro.papotti@unito.it
authors.forename: Mauro
authors.initials: M
authors.lastname: Papotti
authors.forename: Marco
authors.initials: M
authors.lastname: Volante
authors.forename: Enrico
authors.initials: E
authors.lastname: Saggiorato
authors.forename: Desiree
authors.initials: D
authors.lastname: Deandreis
authors.forename: Andrea
authors.initials: A
authors.lastname: Veltri
authors.forename: Fabio
authors.initials: F
authors.lastname: Orlandi
mesh_terms: D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000737:chemistry* / Q000473:pathology*; D004847:Epithelial Cells / Q000737:chemistry / Q000473:pathology; D005260:Female; D037502:Galectin 3 / Q000032:analysis*; D006801:Humans; D007124:Immunoenzyme Techniques; D007633:Keratins / Q000032:analysis; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000737:chemistry* / Q000473:pathology*
chemical_list: D037502:Galectin 3; D007633:Keratins