title: Thyroid tumors of uncertain malignant potential: morphologic and imunohistochemical analysis of 29 cases.
abstract: BACKGROUND
  Thyroid tumors of uncertain malignant potential (TT-UMP) include follicular and well-differentiated tumors of UMP (FT-UMP/WDT-UMP), as it refers to the presence of questionable capsular/vascular invasion or incompletely developed papillary thyroid carcinoma (PTC)-type nuclear changes. However, these tumors are difficult to diagnose in most cases. We aimed to investigate whether immunohistochemistry (HBME-1, cytokeratin-19, galectin-3, CD56 and p63) provides additional information concerning such lesions.
  
  
  METHODS
  We performed an immunohistochemical analysis on 29 TT-UMP cases (22 WDTs-UMP and 7 FTs-UMP) selected from the Rhone Alpes thyroid cancer registry and Departement of Pathology, Tîrgu-Mureş Emergency County Hospital database. The clinicopathological and follow-up data were obtained.
  
  
  RESULTS
  In the WDT-UMP group, HBME-1 was positive in 9/22 (40.9%) cases. CD56, a marker whose expression is reduced or absent in thyroid carcinoma, showed a "malignant" profile (no expression) in 13/22 (59.1%) cases. 7/22 (31.9%) cases were both HBME-1+ and CD56-. One case showed the co-expression of HBME-1, CD56, galectin-3 and cytokeratin-19. In the FT-UMP group, two cases were positive for HBME-1, other two for both galectin-3 and CK19 and only one case revealed a "malignant" CD56 profile. The follow-up data showed no distant metastases or persistent disease.
  
  
  CONCLUSIONS
  Our study demonstrated very heterogeneous immunohistochemical profiles for TTs-UMP, further supporting the borderline nature of these lesions. WDTs-UMP revealed a certain tendency toward a PTC profile, suggesting a possible pathogeneticlink between these two entities. However, immunohistochemistry is still to be regarded more as a supporting diagnostic tool, while morphological criteria should always prime in the diagnostic decision.
authors.affiliation: Department of Histology, University of Medicine and Pharmacy, 38 Gheorghe Marinescu Str, Tîrgu-Mureş 540000, Romania.
authors.forename: Adela
authors.initials: A
authors.lastname: Nechifor-Boila
authors.affiliation: Department of Histology, University of Medicine and Pharmacy, 38 Gheorghe Marinescu Str, Tîrgu-Mureş 540000, Romania. Electronic address: angela.borda@umftgm.ro.
authors.forename: Angela
authors.initials: A
authors.lastname: Borda
authors.affiliation: Registre Rhône Alpin des cancers thyroïdiens, Centre de Médecine Nucléaire, Groupement Hospitalier Est, Hospices Civils de Lyon, 69677 Bron Cedex, France.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Sassolas
authors.affiliation: Registre Rhône Alpin des cancers thyroïdiens, Centre de Médecine Nucléaire, Groupement Hospitalier Est, Hospices Civils de Lyon, 69677 Bron Cedex, France.
authors.forename: Zakia
authors.initials: Z
authors.lastname: Hafdi-Nejjari
authors.affiliation: Department of Endocrinology, University of Medicine and Pharmacy, 38 Gheorghe Marinescu Str, Tîrgu-Mureş 540000, Romania.
authors.forename: Ramona
authors.initials: R
authors.lastname: Cătană
authors.affiliation: Department of Endocrinology, Groupe Hospitalier Est, Hospices Civils de Lyon, Université Lyon 1, 59 boulevard Pinel, 69677 Bron Cedex, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Borson-Chazot
authors.affiliation: Department of Pathology, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Université Lyon 1, 69495 Pierre Bénite, France.
authors.forename: Nicole
authors.initials: N
authors.lastname: Berger
authors.affiliation: Department of Pathology, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Université Lyon 1, 69495 Pierre Bénite, France.
authors.forename: Myriam
authors.initials: M
authors.lastname: Decaussin-Petrucci
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001798:Blood Proteins; D019002:CD56 Antigen / Q000378:metabolism*; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology*; D002291:Carcinoma, Papillary; D005260:Female; D005500:Follow-Up Studies; D037502:Galectin 3 / Q000378:metabolism; D037161:Galectins; D006801:Humans; D007150:Immunohistochemistry; D053539:Keratin-19 / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008875:Middle Aged; D000077273:Thyroid Cancer, Papillary; D013961:Thyroid Gland / Q000378:metabolism / Q000473:pathology; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology*; D055815:Young Adult; D000951:Antigens, Neoplasm
chemical_list: D014408:Biomarkers, Tumor; D001798:Blood Proteins; D019002:CD56 Antigen; D037502:Galectin 3; D037161:Galectins; D053539:Keratin-19; D008565:Membrane Proteins; C081876:CKAP4 protein, human; C432845:HBME-1 antigen; D000951:Antigens, Neoplasm; C428445:LGALS3 protein, human; C522918:NCAM1 protein, human
keywords: CD56 antigen; HBME-1 antigen; Immunohistochemistry; Thyroid tumors of uncertain malignant potential