AccScience Publishing / ARNM / Online First / DOI: 10.36922/ARNM025390050
Submit to ARNM
Cite this article
7
Download
90
Views
Journal Browser
Volume | Year
Issue
Search
Forthcoming Issue
Current Issue
View All
News and Announcements
View All
REVIEW ARTICLE

Incidental pituitary uptake on FDG PET/CT: Physiologic variants, pitfalls, and pathologic mimics

Marwah Abdulrahman1 ,  Raghad M. Al-Houwari1 ,  Manar W. Alomari1 ,  Rezhan Ali1 ,  Shahed Obeidat1 ,  Akram Al-Ibraheem1,2*
Show Less
1 Department of Nuclear Medicine, King Hussein Cancer Center, Amman, Jordan
2 Department of Radiology and Nuclear Medicine, School of Medicine, University of Jordan, Amman, Jordan
ARNM, 025390050 https://doi.org/10.36922/ARNM025390050
Received: 24 September 2025 | Revised: 26 October 2025 | Accepted: 25 November 2025 | Published online: 8 December 2025
© 2025 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
Download PDF
XML
Cite
Abstract

Incidental pituitary uptake on 18F-deoxy-glucose positron emission tomography combined with computed tomography (18F-FDG PET/CT) is rare, occurring in <1% of scans, yet its identification carries significant clinical implications. Accurate interpretation requires a systematic diagnostic approach integrating metabolic, structural, and hormonal assessment. While the normal pituitary gland demonstrates low-level or background FDG activity, focal uptake may suggest pathology ranging from physiologic hyperplasia and benign adenomas to inflammatory conditions such as hypophysitis, or malignant etiologies including pituitary neuroendocrine tumors and metastatic disease. The intensity of uptake, quantified by the maximum standardized uptake value (SUVmax), serves as a critical diagnostic indicator; an SUVmax threshold above 4.1 has been proposed to differentiate benign from malignant lesions with high sensitivity and specificity. Complementary pituitary magnetic resonance imaging (MRI) offers essential anatomic correlation to define lesion morphology, extension, and contrast enhancement patterns, while endocrine evaluation helps establish functional activity and hormonal imbalance. Histopathologic confirmation remains reserved for cases with inconclusive imaging or atypical presentation. This review synthesizes available literature, emphasizing PET-based metabolic features and interpretive pitfalls, while acknowledging the role of computed tomography and MRI in comprehensive lesion characterization. Early recognition and appropriate follow-up are crucial to avoid misdiagnosis and to guide timely management of clinically significant pituitary lesions.

Keywords
Pituitary uptake
Incidentaloma
FDG PET/CT
Differential diagnosis
Funding
None.
Conflict of interest
The authors declare they have no competing interests.
References
  1. Pencharz D, Nathan M, Wagner TL. Evidence-based management of incidental focal uptake of fluorodeoxyglucose on PET-CT. Br J Radiol. 2018;91(1084):20170774. doi: 10.1259/bjr.20170774

 

  1. Jain A, Usmani S, Al Riyami K, et al. High physiological 18 F-FDG uptake in normal pituitary gland on digital PET scanner. World J Nucl Med. 2024;23(3):161-167. doi: 10.1055/s-0044-1786733

 

  1. Jeong SY, Lee SW, Lee HJ, et al. Incidental pituitary uptake on whole-body 18F-FDG PET/CT: A multicentre study. Eur J Nucl Med Mol Imaging. 2010;37(12):2334-2343. doi: 10.1007/s00259-010-1571-5

 

  1. Asa SL, Ezzat S, Mete O. Clinical integration and application of the 2022 WHO pituitary tumor classification. Neurooncol Adv. 2025;7(Suppl 1):i10-i16. doi: 10.1093/noajnl/vdae145

 

  1. Ju H, Zhou J, Pan Y, LV J, Zhang Y. Evaluation of pituitary uptake incidentally identified on 18F-FDG PET/CT scan. Oncotarget. 2017;8(33):55544-55549. doi: 10.18632/oncotarget.15417

 

  1. Britt CJ, Maas AM, Kennedy TA, Hartig GK. Incidental findings on FDG PET/CT in head and neck cancer. Otolaryngol--Head Neck Surg. 2018;158(3):484-488. doi: 10.1177/0194599817742579

 

  1. Weng JH, Lee JK, Wu MF, Shen CY, Kao PF. Pituitary FDG uptake in a patient of lung cancer with bilateral adrenal metastases causing adrenal cortical insufficiency. Clin Nucl Med. 2011;36(8):731-732. doi: 10.1097/RLU.0b013e31821a26bf

 

  1. Ding Y, Wu S, Xu J, Wang H, Ma C. Pituitary 18F-FDG uptake correlates with serum TSH levels in thyroid cancer patients on 18F-FDG PET/CT. Nucl Med Commun. 2019;40(1):57-62. doi: 10.1097/MNM.0000000000000940

 

  1. Hu G, Huo L, Li F, Luo Y. Renal involvement of immunoglobulin G4-related disease presenting as a solitary hypermetabolic mass mimicking renal tumor on 18 F-FDG PET/CT. Clin Nucl Med. 2023;48(8):e400-e402. doi: 10.1097/RLU.0000000000004721

 

  1. Kong Z, Wang Y, Ma W, Cheng X. Role of 18F-fluorodeoxyglucose (FDG) and 18F-2-fluorodeoxy sorbitol (FDS) in autoimmune hypophysitis: A case report. BMC Endocr Disord. 2020;20(1):84. doi: 10.1186/s12902-020-00567-8

 

  1. Kubo H, Ohtsubo H, Shiraoka A, Watanabe M, Kyoraku I, Okamoto K. [A case of suspected IgG4-related hypophysitis presented with panhypopituitarism and central diabetes insipidus]. Rinsho Shinkeigaku. 2024;64(6):398-402. doi: 10.5692/clinicalneurol.cn-001934

 

  1. Van Der Hiel B, Blank CU, Haanen JBAG, Stokkel MPM. Detection of early onset of hypophysitis by (18)F-FDG PET-CT in a patient with advanced stage melanoma treated with ipilimumab. Clin Nucl Med. 2013;38(4):e182-e184. doi: 10.1097/RLU.0b013e3182639765

 

  1. Galligan A, Iravani A, Lasocki A, et al. Imaging for assessment of cancer treatment response to immune checkpoint inhibitors can be complementary in identifying hypophysitis. Front Endocrinol. 2023;14:1295865. doi: 10.3389/fendo.2023.1295865

 

  1. Berntsson SG, Elmgren A, Gudjonsson O, Grabowska A, Landtblom AM, Moraes-Fontes MF. A comprehensive diagnostic approach in suspected neurosarcoidosis. Sci Rep. 2023;13(1):6539. doi: 10.1038/s41598-023-33631-z

 

  1. Li C, Zou Y, Lu X, Wang G, Shu X. Pituitary dysfunction in patients with ANCA associated vasculitis: Prevalence, presentation, and outcomes. Ther Adv Chronic Dis. 2020;11:2040622320930636. doi: 10.1177/2040622320930636

 

  1. Ding H, Li Y, Ruan C, et al. Chinese Erdheim-Chester disease: Clinical-pathology-PET/CT updates. Endocrinol Diabetes Metab Case Rep. 2015;2015:150055. doi: 10.1530/EDM-15-0055

 

  1. Stanly A, Sunny SS, Benjamin J, et al. Utility of F18-FDG PET/CT in the evaluation of pituitary uptake. World J Nucl Med. 2024;23(4):234-241. doi: 10.1055/s-0044-1787967

 

  1. Hyun SH, Choi JY, Lee KH, Choe YS, Kim BT. Incidental focal 18F-FDG uptake in the pituitary gland: Clinical significance and differential diagnostic criteria. J Nucl Med. 2011;52(4):547-550. doi: 10.2967/jnumed.110.083733

 

  1. Usui Y, Kurokawa R, Fukushima T, et al. Ectopic pituitary neuroendocrine tumor arising in the sphenoid sinus withan avid 18F-fluorodeoxyglucose uptake masquerading as malignancy: A case report. Radiol Case Rep. 2023;18(9): 2943-2947. doi: 10.1016/j.radcr.2023.05.063

 

  1. Miljić D, Manojlović-Gačić E, Skender-Gazibara M, et al. All that glitters on PET is not cancer! 18F-deoxy-glucose avidity versus tumor biology: Pituitary incidentaloma in a survivor of two previous unrelated malignancies. Endokrynol Pol. 2017;68(3):352-359. doi: 10.5603/EP.2017.0027

 

  1. Viña JR, Page RB, Davis DW, Hawkins RA. Aerobic glycolysis by the pituitary gland in vivo. J Neurochem. 1984;42(5): 1479-1482. doi: 10.1111/j.1471-4159.1984.tb02814.x

 

  1. Boyle J, Patronas NJ, Smirniotopoulos J, et al. CRH stimulation improves 18F-FDG-PET detection of pituitary adenomas in Cushing’s disease. Endocrine. 2019;65(1):155-165. doi: 10.1007/s12020-019-01944-7

 

  1. Seok H, Lee EY, Choe EY, et al. Analysis of 18F-fluorodeoxyglucose positron emission tomography findings in patients with pituitary lesions. Korean J Intern Med. 2013;28(1):81-88. doi: 10.3904/kjim.2013.28.1.81

 

  1. Karapolat I, Oncel G, Kumanlıoğlu K. Clinically occult pituitary adenoma can appear as a hypermetabolic lesion on whole body FDG PET imaging in a patient with lymphoma. Mol Imaging Radionucl Ther. 2013;22(1):18-20. doi: 10.4274/Mirt.258

 

  1. Albano D, Bosio G, Bertagna F. Incidental pituitary adenoma detected by 18F-FDG PET/CT and 18F-choline PET/CT in the same patient. Rev Espanola Med Nucl E Imagen Mol. 2018;37(4):250-252. doi: 10.1016/j.remn.2017.07.002

 

  1. Zhou J, Ju H, Zhu L, Pan Y, Lv J, Zhang Y. Value of fluorine- 18-fluorodeoxyglucose PET/CT in localizing the primary lesion in adrenocorticotropic hormone-dependent Cushing syndrome. Nucl Med Commun. 2019;40(5):539-544. doi: 10.1097/MNM.0000000000000989

 

  1. Kim K, Kim DK, Moon JH, et al. Dexamethasone suppression for 18F-FDG PET/CT to localize ACTH-secreting pituitary tumors. Cancer Imaging. 2023;23(1):85. doi: 10.1186/s40644-023-00600-8

 

  1. Ginet M, Cuny T, Schmitt E, Marie PY, Verger A. 18F-FDOPA PET imaging in prolactinoma. Clin Nucl Med. 2017;42(8):e383-e384. doi: 10.1097/RLU.0000000000001721

 

  1. Zhong C, Yin S, Zhou P, Jiang S. Pituitary atypical adenoma or carcinoma sensitive to temozolomide combined with radiation therapy: A case report of early identification and management. Turk Neurosurg. 2014;24(6):963-966. doi: 10.5137/1019-5149.JTN.9629-13.1

 

  1. Cheng X, Zhu W, Cui R. Increased 18F-2-fluorodeoxysorbitol (18F-FDS) activity in a pituitary spindle cell carcinoma. Clin Nucl Med. 2016;41(12):953-955. doi: 10.1097/RLU.0000000000001391 31. Habu M, Tokimura H, Hirano H, et al. Pituitary metastases: Current practice in Japan. J Neurosurg. 2015;123(4): 998-1007. doi: 10.3171/2014.12.JNS14870

 

  1. Komninos J, Vlassopoulou V, Protopapa D, et al. Tumors metastatic to the pituitary gland: Case report and literature review. J Clin Endocrinol Metab. 2004;89(2):574-580. doi: 10.1210/jc.2003-030395

 

  1. Marsh JC, Garg S, Wendt JA, Gielda BT, Turian JV, Herskovic AM. Intracranial metastatic disease rarely involves the pituitary: Retrospective analysis of 935 metastases in 155 patients and review of the literature. Pituitary. 2010;13(3):260-265. doi: 10.1007/s11102-010-0229-4

 

  1. Le Meur C, Campedel L, Kharroubi D, Amrane K. Pituitary metastasis of non-small cell lung cancer with high FDG uptake on PET/CT pituitary metastasis of non-small cell lung carcinoma. Clin Nucl Med. 2022;47(7):e506-e508. doi: 10.1097/RLU.0000000000004179

 

  1. Matejka M, Gellen JS, Kraus T, Griessenauer CJ, Ueberschaer MF. Transnasal endoscopic resection of a pituitary metastasis from a tonsillar squamous cell carcinoma (SCC): A case report and a review of the literature. Cureus. 2025;17(7):e88146. doi: 10.7759/cureus.88146

 

  1. Mormando M, Puliani G, Barnabei A, et al. A rare case of pituitary melanoma metastasis: A dramatic and prolonged response to Dabrafenib-Trametinib therapy. Front Endocrinol. 2020;11:471. doi: 10.3389/fendo.2020.00471

 

  1. Weber MD, Carlstrom LP, Vignolles-Jeong J, et al. Endoscopic endonasal approach for resection of sellar leiomyosarcoma metastasis: Illustrative case. J Neurosurg Case Lessons. 2024;8(11):CASE2435. doi: 10.3171/CASE2435

 

  1. Seymour M, Robertson T, Papacostas J, et al. A woman with visual loss, amenorrhoea and polyuria: The first reported case of nodular lymphocyte-predominant Hodgkin lymphoma presenting with hypopituitarism. Endocrinol Diabetes Metab Case Rep. 2021;2021:20-0100. doi: 10.1530/EDM-20-0100

 

  1. Koiso T, Akutsu H, Takano S, et al. Malignant lymphoma in the parasellar region. Case Rep Med. 2014;2014:747280. doi: 10.1155/2014/747280

 

  1. Piciu A, Mester A, Piciu D. Pituitary metastases discovered by 18F-FDG PET/CT during other cancers monitoring: Are there any differences of SUVs between benign and malignant diseases? Clin Nucl Med. 2021;46(1):e44-e46. doi: 10.1097/RLU.0000000000003313

 

  1. Dejust S, Decoudier B, Higel B, Litre CF, Morland D. Gonadotropin-secreting pituitary macroadenoma complicated with hemorrhagic apoplexy in 18F-FDG PET/ CT. Clin Nucl Med. 2021;46(9):748-749. doi: 10.1097/RLU.0000000000003710

 

  1. Kaida H, Matsukubo Y, Im SW, Kashiwagi N, Ishii K. High 18F-FDG uptake in a papillary craniopharyngioma of the third ventricle. Clin Nucl Med. 2023;48(3):245-247. doi: 10.1097/RLU.0000000000004562

 

  1. Cheng ML, Zhao J, Lin Y, Qiu HS. Pituicytoma: Four cases with unusual imaging features and a literature review. Neuro Endocrinol Lett. 2021;42(7):425-432.

 

  1. Feng Z, He D, Mao Z, et al. Utility of 11C-methionine and 18F-FDG PET/CT in patients with functioning pituitary adenomas. Clin Nucl Med. 2016;41(3):e130-e134. doi: 10.1097/RLU.0000000000001085

 

  1. Beyhan E, Erol Fenercioğlu Ö, Karagöz Y, Ergül N, Çermik TF. Mild 68Ga PSMA-11 uptake in incidental pituitary adenoma. Mol Imaging Radionucl Ther. 2022;31(3):244-245. doi: 10.4274/mirt.galenos.2021.97752

 

  1. Maffione AM, Mandoliti G, Pasini F, Colletti PM, Rubello D. Pituitary non-functioning adenoma disclosed at 18F-choline PET/CT to investigate a prostate cancer relapse. Clin Nucl Med. 2016;41(10):e460-461. doi: 10.1097/RLU.0000000000001328

 

  1. Zhang W, Wu Y, Guo L, Li X, Shen G. [68Ga]GaFAPI PET/CT in the evaluation of Langerhans cell histiocytosis: Comparison with [18]FFDG PET/CT. Eur J Nucl Med Mol Imaging. 2025;52(6):2187-2197. doi: 10.1007/s00259-025-07097-2

 

  1. Cai Y, Liu M, Zhang Y, Du H, Huo L, Jing H. The superiority of [68Ga]Ga-FAPI PET/CT over MRI and [18]FFDG PET/ CT in delineating a rare case of pituitary fibrosarcoma. Eur J Nucl Med Mol Imaging. 2025. doi: 10.1007/s00259-025-07467-w

 

  1. Pan Q, Luo Y, Cao X, Li J, Feng J. Bing-neel syndrome and coexisting pituitary macroadenoma in a patient with waldenström macroglobulinemia revealed by 18F-FDG and 68Ga-pentixafor PET/CT. Diagnostics (Basel). 2023;13(7):1334. doi: 10.3390/diagnostics13071334

 

  1. Law WP, Fiumara F, Fong W, Macfarlane DJ. The ‘double pituitary hot spot’ sign of skull base meningioma on gallium-68-labelled somatostatin analogue PET. J Med Imaging Radiat Oncol. 2013;57(6):680-683. doi: 10.1111/1754-9485.12069

 

  1. Manafi-Farid R, Askari E, Shiri I, et al. [18]FFDG-PET/ CT radiomics and artificial intelligence in lung cancer: Technical aspects and potential clinical applications. Semin Nucl Med. 2022;52(6):759-780. doi: 10.1053/j.semnuclmed.2022.04.004

 

  1. Yang Q, Ke T, Wu J, et al. Preoperative prediction of pituitary neuroendocrine tumor invasion using multiparametric MRI radiomics. Front Oncol. 2025;14:1475950. doi: 10.3389/fonc.2024.1475950

 

  1. Banihashemian SS, Bayat M, Pirayesh E, Divband G, Abolhosseini A, Akbari ME. First experience of radionuclide therapy with 177Lu-FAPI-2286 in a patient with metastatic mediastinal sarcoma. Clin Nucl Med. 2024;49(7):e334-e337. doi: 10.1097/RLU.0000000000005255

 

  1. Sadaghiani MS, Rowe SP, Sheikhbahaei S. Applications of artificial intelligence in oncologic 18F-FDG PET/ CT imaging: A systematic review. Ann Transl Med. 2021;9(9):823. doi: 10.21037/atm-20-6162
Share
Back to top
Advances in Radiotherapy & Nuclear Medicine, Electronic ISSN: 2972-4392 Print ISSN: 3060-8554, Published by AccScience Publishing
We use cookies on our website to ensure you get the best experience.
Read more about our cookies here
Accept