title: Thyroid incidentaloma identified by ¹⁸F-fluorodeoxyglucose positron emission tomography with CT (FDG-PET/CT): clinical and pathological relevance.
abstract: OBJECTIVE
  The percentage of patients with thyroid cancer incidentally diagnosed during a (18) F-fluorodeoxyglucose Positron Emission Tomography with computed tomography (CT) (FDG-PET/CT) for nonthyroid diseases ranges between 26% and 50%.
  
  
  METHODS
  Retrospective assessment of the clinical and pathological features of thyroid incidentalomas at FDG-PET/CT, aiming to identify potential predictors of malignancy.
  
  
  METHODS
  Fifty-two patients with incidental thyroid uptake at FDG-PET/CT were retrospectively included [38 W, age 64·1 ± 12·5 years (mean ± SD)]. An arbitrary cut-off level of 5·0 for the 'maximum standardized uptake value' (SUV max) was chosen to differentiate benign from malignant tumours. Complete thyroid function, neck ultrasonography (US) features, and cyto-histological results were reported for all cases.
  
  
  RESULTS
  In our institution, the prevalence of incidental thyroid (18) F-fluorodeoxyglucose ((18) F-FDG) uptake was nearly 1·76%. The prevalence of focal uptake correlated with greater risk of malignancy (P < 0·01). In particular, the euthyroidism (P < 0·003) and a SUV max >5·0 (P < 0·0001) were associated with the diagnosis of thyroid cancer. Diffusely increased FDG-PET/CT uptake in the thyroid was related to benign conditions.
  
  
  CONCLUSIONS
  The presence of focal uptake with high SUV max and euthyroidism correlate with high likelihood of malignancy. Performing a neck US would have to be recommended in all patients with euthyroidism and an incidental FDG-PET/CT focal thyroid uptake. We do not suggest to use FDG-PET/CT as a screening tool for thyroid cancer in the general population, because of both its high cost and low incidence of thyroid incidentaloma at FDG-PET/CT.
authors.affiliation: Endocrinology, Department of Clinical and Experimental Medicine, AOU Maggiore della Carita, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Pagano
authors.forename: M T
authors.initials: MT
authors.lastname: Samà
authors.forename: F
authors.initials: F
authors.lastname: Morani
authors.forename: F
authors.initials: F
authors.lastname: Prodam
authors.forename: M
authors.initials: M
authors.lastname: Rudoni
authors.forename: R
authors.initials: R
authors.lastname: Boldorini
authors.forename: G
authors.initials: G
authors.lastname: Valente
authors.forename: P
authors.initials: P
authors.lastname: Marzullo
authors.forename: R
authors.initials: R
authors.lastname: Baldelli
authors.forename: M
authors.initials: M
authors.lastname: Appetecchia
authors.forename: C
authors.initials: C
authors.lastname: Isidoro
authors.forename: G
authors.initials: G
authors.lastname: Aimaretti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18