18F-Fluorodeoxyglucose Uptake in Thyroid from Positron Emission Tomogram (PET) for Evaluation in Cancer Patients: High Prevalence of Malignancy in Thyroid PET Incidentaloma

Abstract

Our data suggest that a cytologic diagnosis of focal thyroid FDG-PET incidentaloma regardless of SUV is mandatory considering the very high prevalence of thyroid malignancy.

Incidental thyroid “PETomas”: clinical significance and novel description of the self-resolving variant of focal FDG-PET thyroid uptake

“…[3][4][5][6][7][8][9][10][11] In contrast, diffuse, bilateral FDG-PET uptake is usually associated with benign disease (Table 3) In the current study, the prevalence of cancer was 30% (9/30) for those in whom a confirmed cytologic or histologic diagnosis was obtained via FNAC or surgery, and this incidence was similar to that reported by others. [3][4][5][6][7][8][9][10][11] The overall incidence of cancer in the current series was relatively low at 8.7% (9 of 103). Because more than half of the patients with PETomas (53 of 103) did not undergo further evaluation with either ultrasonography, FNAC or surgery, the true prevalence of cancer is arguably underestimated.…”

“…[3][4][5][6][7][8][9][10][11] Moreover, the prevalence of malignancy within these PETomas is remarkably high at 14%-56%. [3][4][5][6][7][8][9][10][11] In contrast, diffuse, bilateral FDG-PET uptake is usually associated with benign disease (Table 3) In the current study, the prevalence of cancer was 30% (9/30) for those in whom a confirmed cytologic or histologic diagnosis was obtained via FNAC or surgery, and this incidence was similar to that reported by others. [3][4][5][6][7][8][9][10][11] The overall incidence of cancer in the current series was relatively low at 8.7% (9 of 103).…”

“…Most previous studies, however, failed to show the benefit of SUV to differentiate benign from malignant PETomas. 3,9,10 Although maximum SUV is sometimes clinically useful in differentiating some malignancies, it is subject to variability because of the patient's body composition, period of uptake, lesion size, partial volume averaging and plasma glucose. 11 Also, many PETomas are subcentimetre, and thus maximum SUV may not be accurately calculated.…”

“…Several reports have described incidentally detected focal thyroid lesions on FDG-PET in patients with no history of thyroid pathology. [3][4][5][6][7][8][9][10][11] We refer to these incidentalomas as "PETomas." The overall reported incidence of FDG-PET thyroid PETomas varies from 1.1% to 4.0%, [3][4][5][6][7][8][9][10][11] whereas the prevalence of thyroid cancer in these series is remarkably high, ranging from 14% to 56%.…”

“…The overall reported incidence of FDG-PET thyroid PETomas varies from 1.1% to 4.0%, [3][4][5][6][7][8][9][10][11] whereas the prevalence of thyroid cancer in these series is remarkably high, ranging from 14% to 56%. [3][4][5][6][7][8][9][10][11] Adequate management of thyroid incidentalomas is not well established. Because most thyroid incidentalomas are small, observation is a reasonable option for patients with benign cytology and no obvious risk factors.…”