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Year : 2012  |  Volume : 27  |  Issue : 3  |  Page : 187-188  

Diffusely increased thyroidal uptake of F-18 fluorodeoxyglucose in a patient with non-Hodgkin's lymphoma and Graves' disease

Department of Nuclear Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India

Date of Web Publication31-May-2013

Correspondence Address:
Anish Bhattacharya
Department of Nuclear Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh-160 012
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0972-3919.112728

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Increased uptake of F-18 fluorodeoxyglucose (FDG) has been reported in thyroiditis and hypothyroidism. The authors present a case where increased FDG uptake in the thyroid was subsequently corroborated with a pertechnetate scan and thyroid hormone levels to diagnose previously undetected Graves' disease in a patient of non-Hodgkin's lymphoma being followed-up with positron emission tomography for disease recurrence.

Keywords: F-18 fluorodeoxyglucose, Graves′ disease, non-Hodgkin′s lymphoma, pertechnetate scan, thyroid

How to cite this article:
Kamaleshwaran KK, Kashyap R, Harisankar CN, Bhattacharya A, Mittal BR. Diffusely increased thyroidal uptake of F-18 fluorodeoxyglucose in a patient with non-Hodgkin's lymphoma and Graves' disease. Indian J Nucl Med 2012;27:187-8

How to cite this URL:
Kamaleshwaran KK, Kashyap R, Harisankar CN, Bhattacharya A, Mittal BR. Diffusely increased thyroidal uptake of F-18 fluorodeoxyglucose in a patient with non-Hodgkin's lymphoma and Graves' disease. Indian J Nucl Med [serial online] 2012 [cited 2022 Jan 20];27:187-8. Available from:

   Introduction Top

Planar thyroid scintigraphy showing increased 99mTcO4 (pertechnetate) uptake is the hallmark of Graves' disease, and is used to differentiate this condition from thyroiditis. However, diffuse uptake of F-18 fluorodeoxyglucose (FDG) in the thyroid is usually associated with thyroiditis. This case illustrates an alternate clinical possibility for increased thyroidal FDG uptake.

   Case Report Top

A 63-year-old female patient with non-Hodgkin's lymphoma in remission for the last 2 years after chemotherapy was referred to our department for a whole body FDG-positron emission tomography (PET)/computed tomography scan to assess for disease recurrence after recent onset of diplopia and raised β2-microglobulin levels. Multiple lymph nodes in the cervical, mediastinal and right axillary regions showed increased metabolic activity, suggestive of recurrence. In addition, diffusely increased FDG uptake was seen in both lobes of the thyroid gland on the whole body PET image [Figure 1]a, with a standardized uptake value of 12.3. On clinical examination, she was found to have bilateral exophthalmos and the biochemical profile showed high T3 and T4 and low thyroid stimulating hormone values, suggestive of hyperthyroidism. Subsequently, a 99mTcO 4 (pertechnetate) scan [Figure 1]b, also showed diffusely increased tracer uptake in the thyroid gland; uptake at 20 min was 6.1%. A diagnosis of Graves' disease was made and treatment with Carbimazole was started.
Figure 1: (a) Whole body fluorodeoxyglucose (FDG)-positron emission tomography (maximum intensity projection image) showing diffusely increased uptake of FDG in both lobes of the thyroid gland. Multiple FDG avid axillary and mediastinal nodes are also seen. (b) 99mTc pertechentate scan showing homogenously increased tracer uptake in both lobes of the thyroid gland

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   Discussion Top

The value of FDG PET for the diagnosis of several diseases affecting the thyroid gland has been demonstrated, and there is a growing evidence that this investigation may help in differentiating malignant from benign disease. [1],[2] With increasing use of whole body FDG-PET in clinical practice, incidental focal or diffuse FDG uptake in the thyroid is being detected more frequently. Diffusely increased FDG uptake in the thyroid has been reported in 0.6-3.3% of the cases. Although, some authors believe that this may be a normal occurrence, [3] other studies suggest that such uptake is primarily associated with autoimmune thyroiditis or hypothyroidism. [4] Diffuse thyroidal FDG uptake is most commonly benign and is usually caused by chronic lymphocytic (Hashimoto's) thyroiditis. [5] In a few other cases, diffuse thyroid FDG uptake has also been linked to Graves' disease. [6],[7] The added visualization of the thymus gland and FDG uptake in the skeletal muscles has been described as characteristic of Graves' disease. [8],[9] The present case shows that increased FDG uptake in the thyroid may also be seen in this condition without any thymic or skeletal muscle involvement. The exact mechanism of increased thyroidal uptake of FDG is not well-established. Graves' disease with significant infiltration and activation of T lymphocytes in the thyroid and thymus can induce upregulation of Glucose transporter 1 (GLUT1), which is the major isoform of glucose transporter in the T lymphocytes. [10]

   References Top

1.Zhuang H, Kumar R, Mandel S, Alavi A. Investigation of thyroid, head, and neck cancers with PET. Radiol Clin North Am 2004;42:1101-11.  Back to cited text no. 1
2.Gordon BA, Flanagan FL, Dehdashti F. Whole-body positron emission tomography: Normal variations, pitfalls, and technical considerations. AJR Am J Roentgenol 1997;169:1675-80.  Back to cited text no. 2
3.Shreve PD, Anzai Y, Wahl RL. Pitfalls in oncologic diagnosis with FDG PET imaging: Physiologic and benign variants. Radiographics 1999;19:61-77.  Back to cited text no. 3
4.Yasuda S, Shohtsu A, Ide M, Takagi S, Takahashi W, Suzuki Y, et al. Chronic thyroiditis: Diffuse uptake of FDG at PET. Radiology 1998;207:775-8.  Back to cited text no. 4
5.Karantanis D, Bogsrud TV, Wiseman GA, Mullan BP, Subramaniam RM, Nathan MA, et al. Clinical significance of diffusely increased 18F-FDG uptake in the thyroid gland. J Nucl Med 2007;48:896-901.  Back to cited text no. 5
6.Santiago JF, Jana S, El-Zeftawy H, Naddaf S, Abdel-Dayem HM. Increased F-18 fluorodeoxyglucose thyroidal uptake in Graves' disease. Clin Nucl Med 1999;24:714-5.  Back to cited text no. 6
7.Goethals I, Mervillie K, De Winter O, Delrue L, Mekeirele K, Ham H. Mismatch of F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) and Tc-99m pertechnetate single photon emission computer tomography (SPECT) in a euthyroid multinodular goiter. Clin Nucl Med 2007;32:6-8.  Back to cited text no. 7
8.Chen YK, Wang YF, Chiu JS. Diagnostic trinity: Graves' disease on F-18 FDG PET. Clin Nucl Med 2007;32:816-7.  Back to cited text no. 8
9.Chen YK, Chen YL, Liao AC, Shen YY, Kao CH. Elevated 18F-FDG uptake in skeletal muscles and thymus: A clue for the diagnosis of Graves' disease. Nucl Med Commun 2004;25:115-21.  Back to cited text no. 9
10.Boerner AR, Voth E, Theissen P, Wienhard K, Wagner R, Schicha H. Glucose metabolism of the thyroid in Graves' disease measured by F-18-fluoro-deoxyglucose positron emission tomography. Thyroid 1998;8:765-72.  Back to cited text no. 10


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