To investigate and evaluate the prevalence of incidental thyroid diffuse and diffuse-plus-focal fluorine-18 fluorodeoxyglucose (FDG) uptake in healthy subjects who underwent cancer screening on positron emission tomography (PET) scan, and also to evaluate the prevalence of thyroid cancer and Hashimoto's thyroiditis.
We carried out a retrospective review of 1626 subjects who underwent PET scanning at our institution. Diffuse uptake was defined as FDG uptake in the whole thyroid gland, whereas diffuse-plus-focal uptake was defined as a thyroid lesion with both diffuse uptake and focal FDG uptake. The maximum standardized uptake value of the thyroid lesions was recorded and reviewed. In each selected subject with positive thyroid FDG uptake, serum thyroid-stimulating hormone, thyroid hormone, and thyroid antibodies were measured. Fine needle aspiration cytology was performed on patients with a definite nodule using ultrasonography.
Twenty-nine subjects (1.78%) were identified as having either diffuse FDG uptake (n = 25, 1.53%) or diffuse-plus-focal FDG uptake (n = 4, 0.24%). All subjects with diffuse FDG uptake were diagnosed as having Hashimoto's thyroiditis. In 1 of the 25 subjects with diffuse FDG uptake and two of the four with diffuse-plus-focal FDG uptake, histopathologic diagnosis showed papillary thyroid carcinoma associated with Hashimoto's thyroiditis. However, PET scan did not detect papillary carcinoma associated with Hashimoto's thyroiditis in one of the three subjects.
Our results suggest that although diffuse FDG uptake usually indicates Hashimoto's thyroiditis, the risk of thyroid cancer must be recognized in both diffuse FDG uptake and diffuse-plus-focal FDG uptake on PET scan.
FDG-PET Diffuse FDG uptake Cancer screening Hashimoto's thyroiditis Thyroid cancer
This is a preview of subscription content, log in to check access.
Yasuda, S, Shohtsu, A 1997Cancer screening with whole-body 18F-fluorodeoxyglucose positron-emission tomographyLancet3501819PubMedCrossRefGoogle Scholar
Chen, YK, Ding, HJ, Chen, KT, Chen, YL, Liao, AC, Shen, YY, et al. 2005Prevalence and risk of cancer of focal thyroid incidentaloma identified by 18F-fluorodeoxyglucose positron emission tomography for cancer screening in healthy subjectsAnticancer Res2514216PubMedGoogle Scholar
Schoder, H, Yeung, HW 2004Positron emission imaging of head and neck cancer, including thyroid carcinomaSemin Nucl Med3418097PubMedCrossRefGoogle Scholar
Yasuda, S, Shohtsu, A, Ide, M, Takagi, S, Takahashi, W, Suzuki, Y, et al. 1998Chronic thyroiditis: diffuse uptake of FDG at PETRadiology2077758PubMedGoogle Scholar
Ramos, CD, Chisin, R, Yeung, HW, Larson, SM, Macapinlac, HA 2001Incidental focal thyroid uptake on FDG positron emission tomographic scans may represent a second primary tumorClin Nucl Med261937PubMedCrossRefGoogle Scholar
Yasuda, S, Ide, M, Fujii, H, Nakahara, T, Mochizuki, Y, Takahashi, W, et al. 2000Application of positron emission tomography imaging to cancer screeningBr J Cancer83160711PubMedCrossRefGoogle Scholar
Kang, KW, Kim, SK, Kang, HS, Lee, ES, Sim, JS, Lee, IG, et al. 2003Prevalence and risk of cancer of focal thyroid incidentaloma identified by 18F-fluorodeoxyglucose positron emission tomography for metastasis evaluation and cancer screening in healthy subjectsJ Clin Endocrinol Metab8841004PubMedCrossRefGoogle Scholar
Kim, TY, Kim, WB, Ryu, JS, Gong, G, Hong, SJ, Shong, YK 200518F-fluorodeoxyglucose uptake in thyroid from positron emission tomogram (PET) for evaluation in cancer patients: high prevalence of malignancy in thyroid PET incidentalomaLaryngoscope11510748PubMedCrossRefGoogle Scholar
Cohen, MS, Arslan, N, Dehdashti, F, Doherty, GM, Lairmore, TC, Brunt, LM, et al. 2001Risk of malignancy in thyroid incidentalomas identified by fluorodeoxyglucose-positron emission tomographySurgery1309416PubMedCrossRefGoogle Scholar
Choi, JY, Lee, KS, Kim, HJ, Shim, YM, Kwon, OJ, Park, K, et al. 2006Focal thyroid lesions incidentally identified by integrated 18F-FDG PET/CT: clinical significance and improved characterizationJ Nucl Med4760915PubMedGoogle Scholar
Carmeci, C, Jeffrey, RB, McDougall, IR, Nowels, KW, Weigel, RJ 1998Ultrasound-guided fine-needle aspiration biopsy of thyroid massesThyroid82839PubMedCrossRefGoogle Scholar
Okayasu, I, Fujiwara, M, Hara, Y, Tanaka, Y, Rose, NR 1995Association of chronic lymphocytic thyroiditis and thyroid papillary carcinoma: a study of surgical cases among Japanese, and white and African AmericansCancer7623128PubMedCrossRefGoogle Scholar
Okayasu, I, Saegusa, M, Fujiwara, M, Hara, Y, Rose, NR 1995Enhanced cellular proliferative activity and cell death in chronic thyroiditis and thyroid papillary carcinomaJ Cancer Res Clin Oncol12174652PubMedCrossRefGoogle Scholar
Andrikoula, M, Tsatsoulis, A 1999The role of Fas-mediated apoptosis in thyroid diseaseEur J Endocrinol1445618CrossRefGoogle Scholar
Chakrabarti, R, Jung, CY, Lee, TP, Liu, H, Mookerjee, BK 1994Changes in glucose transport and transporter isoforms during the activation of human peripheral blood lymphocytes by phytohemagglutininJ Immunol15226608PubMedGoogle Scholar
Gamelli, RL, Liu, H, He, LK, Hofmann, CA 1996Augmentations of glucose uptake and glucose transporter-1 in macrophages following thermal injury and sepsis in miceJ Leukoc Biol5963947PubMedGoogle Scholar
Kubota, R, Yamada, S, Kubota, K, Ishiwata, K, Tamahashi, N, Ido, T 1992Intratumoral distribution of fluorine-18-fluorodeoxyglucose in vivo: high accumulation in macrophages and granulation tissues studied by microautoradiographyJ Nucl Med33197280PubMedGoogle Scholar
Schmid, DT, Kneifel, S, Stoeckli, SJ, Padberg, BC, Merrill, G, Goerres, GW 2003Increased 18F-FDG uptake mimicking thyroid cancer in a patient with Hashimoto's thyroiditisEur Radiol13211921PubMedCrossRefGoogle Scholar