title: Cytological evaluation by fine needle aspiration biopsy of incidental focal increased fluorodeoxyglucose uptake in thyroid on positron emission tomography scan.
abstract: BACKGROUND
  With the increased use of whole body fluorodeoxyglucose positron emission tomography (PET) scan for staging/restaging or primary diagnosis of neoplasia, thyroid incidentalomas have become more common. The limited reports of PET-positive thyroid incidentalomas showed incidence of malignancy ranging from 14 to 66%, and there is discrepancy in terms of the diagnostic significance of the standard uptake value (SUV) value.
  
  
  METHODS
  This is a retrospective study of 20 PET incidentalomas which had cytological evaluation from October 2009 to February 2015 at a tertiary care university medical center, M:F = 8:12.
  
  
  RESULTS
  Of the 20 cases, 14 (70%) had a cytological diagnosis of atypia or suspicious for neoplasia. Eleven of those (55%) underwent surgical resection with final diagnosis of PTC in 8 cases, follicular carcinoma in one case (5%), follicular adenoma in one case (5%), and Hurthle cell adenoma in one case (5%). There was good correlation between cytological and histological diagnosis. For two cases with cytological diagnosis of suspicious for follicular neoplasm, no further histological diagnosis was obtained. One patient had direct cytological diagnosis of PTC also did not undergo surgical resection/diagnosis due to the advanced primary pancreatic adenocarcinoma. The remaining 6 (30%) cases had a cytological diagnosis of benign follicular nodule. Furthermore, no significant difference between malignant SUV and benign SUV was observed.
  
  
  CONCLUSIONS
  Malignancy was identified in 50% of the PET-positive incidentalomas in our series. PTC constitutes the major malignant diagnosis. No diagnostic value of SUV was observed to differentiate malignant from benign lesions. Diagn. Cytopathol. 2017;45:501-506. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Department of Pathology, University Hospitals Cleveland Medical Center, Cleveland, Ohio.
authors.forename: Yanchun
authors.identifier: http://orcid.org/0000-0001-6933-3493
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Pathology, University Hospitals Cleveland Medical Center, Cleveland, Ohio.
authors.forename: Min
authors.initials: M
authors.lastname: Cui
authors.affiliation: Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio.
authors.forename: Nami
authors.initials: N
authors.lastname: Azar
authors.affiliation: Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, Ohio.
authors.forename: Dean
authors.initials: D
authors.lastname: Nakamoto
authors.affiliation: Department of Pathology, University Hospitals Cleveland Medical Center, Cleveland, Ohio.
authors.forename: Claire W
authors.initials: CW
authors.lastname: Michael
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000328:Adult; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000592:standards*; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: FNA; PET-positive; incidental nodules; thyroid