Send to

Choose Destination
Surgery. 2001 Dec;130(6):941-6.

Risk of malignancy in thyroid incidentalomas identified by fluorodeoxyglucose-positron emission tomography.

Author information

Department of Surgery, the Siteman Cancer Center, and the Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO 63110, USA.



Thyroid tumors often exhibit increased metabolic activity, as evidenced by enhanced glucose uptake on positron emission tomography (PET) with use of (18)F-fluorodeoxyglucose (FDG). The incidence of new thyroid lesions found on routine FDG-PET has not been previously reported.


A retrospective review of all patients who underwent FDG-PET imaging at our institution from June 1, 1996, through March 15, 2001, identified patients with a newly diagnosed thyroid lesion. Thyroid incidentaloma was defined as a thyroid lesion seen initially on FDG-PET in a patient without a history of thyroid disease. Available follow-up data were documented.


One hundred and two of 4525 FDG-PET examinations (2.3%) demonstrated thyroid incidentalomas. Eighty-seven of 102 patients had no thyroid histology because of other malignancies. Fifteen patients had thyroid biopsy: 7 (47%) with thyroid cancer, 6 (40%) with nodular hyperplasia, 1 with thyroiditis, and 1 with atypical cells of indeterminate origin. The average standardized uptake values were higher for malignant compared with benign lesions.


Thyroid incidentaloma identified by FDG-PET occurred with a frequency of 2.3%. Of the thyroid incidentalomas that underwent biopsy, 47% were found to be malignant. Given the risk of malignancy, patients with new thyroid lesions on PET scan should have a tissue diagnosis if it will influence outcome and management. Standardized uptake values may be helpful in predicting benign versus malignant histology.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center