F FDG PET/CT Axial image
Head & neck imaging
Case TypeClinical Cases
Authors
Teck Jian Choo1,2, James Birchall1,2, James Kirk1
Patient62 years, female
A 62-year-old female patient presented with abdominal lump. CT chest, abdomen and pelvis shows multiple abdominal nodal masses. Biopsy revealed B Cell lymphoma. Current investigation is a 18-F FDG PET/CT performed for response post-R-CHOP chemotherapy showing a 2cm hyper-metabolic right neck mass and multiple avid abdominal masses.
18F-FDG PET/CT : FDG avid, SUV-max 8, right neck lesion at the bifurcation of the common carotid artery measuring 2cm. Multiple hyper-metabolic left supraclavicular, mesenteric, para-aortic and iliac nodes with splenic deposits demonstrates different / higher activity compared to the neck mass, up to SUV-max 32 in the mesenteric nodal mass.
CT neck, chest, abdomen and pelvis: There is an enhancing ovoid shaped right neck mass which appears to be splaying the common carotid artery bifurcation.
Ultrasound neck performed to plan biopsy: Duplex ultrasound shows a highly vascularised solid hypoechoic mass in the area of the carotid bifurcation, with splaying of the bifurcation of the internal and external carotid arteries. Biopsy thus not performed.
MRI neck: The right neck mass shows low T1 signal and high T2 signal. Post contrast there is avid enhancement with low internal signal suggestive of flow voids.
Background
Carotid body tumours, also known as paragangliomas or chemodectomas, are neuroendocrine neoplasms which arise near the carotid bifurcation within glomus cells derived from the embryonic neural crest [1]. Paragangliomas usually are slow-growing and less than 10% are malignant [2]. The carotid body is the most common site of occurrence [3]. Predominantly cases are found in patients ranging from 50 to 70 years of age with a slightly higher prevalence in women [1]. Approximately 40% are thought to be hereditary [4].
Clinical Perspective
Carotid body tumour classically presents as a non-tender, insidiously enlarging neck mass in an asymptomatic patient [5] and incidentally found on imaging [1]. Untreated, they will ultimately result in a progressive enlarging cervical mass involving and causing dysfunction of cranial nerves [6]. There is an increased prevalence of head and neck paragangliomas with familial genetic syndromes such as von Hippel-Lindau disease (VHL), multiple endocrine neoplasia type 2 (MEN2), and type 1 neurofibromatosis (NF1) [7].
Imaging Perspective
Paragangliomas are hyper-metabolic on FDG PET/CT [8,9] and potentially misinterpreted as false positive metastatic lymphadenopathy [9]. On CT, they are highly vascular [3,10] and typically presents as a well-defined soft-tissue mass within the carotid space of the infrahyoid neck [5]. On ultrasound, there is splaying of the bifurcation of the common carotid artery [3,5]. On MRI they have low signal intensity with standard spin-echo short repetition time (TR)/short echo time (TE) and long TR/short TE sequences and a high signal intensity with long TR/long TE sequences. There is intense enhancement post administration of intravenous contrast [3,5]. If suspected, nuclear medicine tests such as Octreotide and I-123 MIBG SPECT/CT may be performed[14].
Outcome
There is good prognosis with surgical treatment [11]. A multidisciplinary team treatment approach is essential. Accurate imaging assessment for the anatomy and preoperative embolisation of large, vascular tumors can facilitate surgical treatment [1,2,6].
Take Home Message / Teaching Points
1. Carotid body tumours are most commonly located at the bifurcation of the common carotid arteries and are characteristically hypervascular in nature.
2. Paraganglioma is an important differential for neck masses to avoid erroneous interpretation of cervical lymphadenopathy.
3. Meticulous evaluation of a hyper-metabolic lesion on FDG PET/CT is essential, remembering causes of false positive findings including synchronous tumours, benign tumours, inflammation, infection, brown fat and physiological uptake [12,13].
[1] Van Trung Hoang, C.T.T., Lai, T.A.K., Doan, D.T. and Tran, T.T.T., 2019. Carotid body tumor: a case report and literature review. Journal of Radiology Case Reports, 13(8), p.19. (PMID: 31558967)
[2] Lee, J.H., Barich, F., Karnell, L.H., Robinson, R.A., Zhen, W.K., Gantz, B.J., Hoffman, H.T. and American College of Surgeons Commission on Cancer and the American Cancer Society, 2002. National Cancer Data Base report on malignant paragangliomas of the head and neck. Cancer, 94(3), pp.730-737. (PMID: 11857306)
[3] Thelen, J. and Bhatt, A.A., 2019. Multimodality imaging of paragangliomas of the head and neck. Insights into imaging, 10(1), p.29. (PMID: 30830483)
[4] Dahia, P.L., 2014. Pheochromocytoma and paraganglioma pathogenesis: learning from genetic heterogeneity. Nature Reviews Cancer, 14(2), pp.108-119. (PMID: 24442145)
[5] Rao, A.B., Koeller, K.K. and Adair, C.F., 1999. From the archives of the AFIP: Paragangliomas of the head and neck: radiologic-pathologic correlation. Radiographics, 19(6), pp.1605-1632. (PMID: 10555678)
[6] Dixon, J.L., Atkins, M.D., Bohannon, W.T., Buckley, C.J. and Lairmore, T.C., 2016, January. Surgical management of carotid body tumors: a 15-year single institution experience employing an interdisciplinary approach. In Baylor University Medical Center Proceedings (Vol. 29, No. 1, pp. 16-20). Taylor & Francis. (PMID: 26722157)
[7] Boedeker, C.C., Erlic, Z., Richard, S., Kontny, U., Gimenez-Roqueplo, A.P., Cascon, A., Robledo, M., de Campos, J.M., van Nederveen, F.H., de Krijger, R.R. and Burnichon, N., 2009. Head and neck paragangliomas in von Hippel-Lindau disease and multiple endocrine neoplasia type 2. The Journal Of Clinical Endocrinology & Metabolism, 94(6), pp.1938-1944. (PMID: 19336503)
[8] Royal College of Physicians of London, Royal College of Physicians and Surgeons of Glasgow, Royal College of Physicians of Edinburgh, Royal College of Radiologists, British Nuclear Medicine Society, Administration of Radioactive Substances Advisory Committee. Evidence-based indications for the use of PET-CT in the United Kingdom 2016. London: The Royal College of Radiologists, 2016. Ref No. BFCR(16)3
[9] Nautiyal, A., Mukherjee, A., Mitra, D., Chatterjee, P. and Roy, A., 2018. Carotid body tumor masquerading as metastatic cervical lymph node on fluorodeoxyglucose positron-emission tomography-computed tomography. Indian journal of nuclear medicine: IJNM: the official journal of the Society of Nuclear Medicine, India, 33(3), p.259. (PMID: 29962732)
[10] O'Neill, S., O'Donnell, M., Harkin, D., Loughrey, M., Lee, B. and Blair, P., 2011. A 22-year Northern Irish experience of carotid body tumours. The Ulster medical journal, 80(3), p.133. (PMID: 23526121)
[11] Wieneke, J.A. and Smith, A., 2009. Paraganglioma: carotid body tumor. Head and neck pathology, 3(4), p.303. (PMID: 20016787)
[12] Long, N.M. and Smith, C.S., 2011. Causes and imaging features of false positives and false negatives on 18 F-PET/CT in oncologic imaging. Insights into imaging, 2(6), pp.679-698. (PMID: 22347986)
[13] Carter, K.R. and Kotlyarov, E., 2007. Common causes of false positive F18 FDG PET/CT scans in oncology. Brazilian Archives of Biology and Technology, 50(SPE), pp.29-35.
[14] King, K.S., Chen, C.C., Alexopoulos, D.K., Whatley, M.A., Reynolds, J.C., Patronas, N., Ling, A., Adams, K.T., Xekouki, P., Lando, H. and Stratakis, C.A., 2011. Functional imaging of SDHx-related head and neck paragangliomas: comparison of 18F-fluorodihydroxyphenylalanine, 18F-fluorodopamine, 18F-fluoro-2-deoxy-D-glucose PET, 123I-metaiodobenzylguanidine scintigraphy, and 111In-pentetreotide scintigraphy. The Journal of Clinical Endocrinology & Metabolism, 96(9), pp.2779-2785. (PMID: 21752889)
URL: | https://www.eurorad.org/case/16970 |
DOI: | 10.35100/eurorad/case.16970 |
ISSN: | 1563-4086 |
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