Thyroid incidentaloma identified by 18F-fluorodeoxyglucose positron emission tomography with CT (FDG-PET/CT): Clinical and pathological relevance

L. Pagano, M. T. Samà, F. Morani, F. Prodam, M. Rudoni, R. Boldorini, G. Valente, P. Marzullo, R. Baldelli, M. Appetecchia, C. Isidoro, Gianluca Aimaretti

Research output: Contribution to journalArticlepeer-review

Abstract

Objective The percentage of patients with thyroid cancer incidentally diagnosed during a 18F-fluorodeoxyglucose Positron Emission Tomography with computed tomography (CT) (FDG-PET/CT) for nonthyroid diseases ranges between 26% and 50%. Design Retrospective assessment of the clinical and pathological features of thyroid incidentalomas at FDG-PET/CT, aiming to identify potential predictors of malignancy. Patients 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 18F-fluorodeoxyglucose (18F-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.

Original languageEnglish
Pages (from-to)528-534
Number of pages7
JournalClinical Endocrinology
Volume75
Issue number4
DOIs
Publication statusPublished - Oct 2011

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism

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