2010, Number 2
Rev Endocrinol Nutr 2010; 18 (2)
Incidental thyroid uptake during 18F-FDG PET/CT: Correlation with pathological findings and clinical implications
Gama-Moreno MG, Mercado M, Padilla-Rodríguez ÁL, García-Ortiz JR, Schalch-Ponce de León JM, Gómez-Méndez M
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ABSTRACTObjective: To investigate the prevalence and significance of incidental thyroid uptake on whole body PET/CT scans. Methods: Retrospective review of 4,908 PET/CT scans performed between 2005 and 2010. Histopathological and cytopathological data was sought on those subjects who showed incidental thyroid uptake. Results: 275 of the 4,908 patients (5.6%) had 18F-FDG increased thyroid uptake: focal in 119 (43.3%), diffuse in 135 (49%) and mixed (focal-diffuse) in 21 (7.7%). Thyroid uptake was more frequent among women regardless of age. Of these 275 patients with thyroid uptake, 29 has cyto/hystopathological information available (20 with focal, 5 with diffuse and 4 with mixed). 50% of the patients with focal uptake had a final malignant diagnosis, usually papillary carcinoma, whereas 90% of those with diffuse or mixed uptake ended up having a benign condition, usually nodular goiter or thyroiditis. SUVmax, age and gender did not correlate with malignant diagnosis. Conclusions: Focal thyroid uptake on PET/CT is associated with a high likelihood of cancer. These patients need to be carefully evaluated with thyroid ultrasound and even aspiration biopsy.