|Year : 2019 | Volume
| Issue : 3 | Page : 260-262
Coexistence of multiple metastatic lesions showing various grades of differentiation in a single patient with neuroendocrine tumor of lung as primary: A combined modality approach of 68Ga-DOTANOC positron emission tomography/computed tomography and 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging
Sarthak Tripathy1, Sanjana Ballal1, Madhav Prasad Yadav1, Prashant Joshi2, Chandrasekhar Bal1, Nishikant Avinash Damle1
1 Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India
2 Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
|Date of Web Publication||20-Jun-2019|
Dr. Chandrasekhar Bal
Professor and HOD, Department of Nuclear Medicine and PET-CT, All India Institute of Medical Sciences, Ansari Nagar, New Delhi - 110 029
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Neuroendocrine tumors (NETs) of gastrointestinal (GI) tract and lungs are a rare variety of tumors but given their indolent nature are quite prevalent. These tumors are mostly malignant in nature and are often diagnosed in advanced stages. GI tracts are the most common sites of NETs followed by lungs, thymus, and other less common sites being ovaries, testis, and hepatobiliary system. Nuclear medicine imaging modalities include 68Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) which is sensitive for low-grade NETs and 18F-fluorodeoxyglucose (FDG) PET/CT which is more valuable for high-grade NETs. However, intermediate-grade NETs are equally sensitive to both 68Ga-DOTANOC PET/CT and 18F-FDG PET/CT.
Keywords: 18F-fluorodeoxyglucose positron emission tomography/computed tomography, 68Ga-DOTANOC positron emission tomography/computed tomography, neuroendocrine tumors
|How to cite this article:|
Tripathy S, Ballal S, Yadav MP, Joshi P, Bal C, Damle NA. Coexistence of multiple metastatic lesions showing various grades of differentiation in a single patient with neuroendocrine tumor of lung as primary: A combined modality approach of 68Ga-DOTANOC positron emission tomography/computed tomography and 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging. Indian J Nucl Med 2019;34:260-2
|How to cite this URL:|
Tripathy S, Ballal S, Yadav MP, Joshi P, Bal C, Damle NA. Coexistence of multiple metastatic lesions showing various grades of differentiation in a single patient with neuroendocrine tumor of lung as primary: A combined modality approach of 68Ga-DOTANOC positron emission tomography/computed tomography and 18F-fluorodeoxyglucose positron emission tomography/computed tomography imaging. Indian J Nucl Med [serial online] 2019 [cited 2020 Feb 20];34:260-2. Available from: http://www.ijnm.in/text.asp?2019/34/3/260/260746
A 55-year-old female consulted the pulmonary medicine department with chief complaints of obstructive pneumonia, chest pain, dyspnea, and cough. Computed tomography (CT)-guided biopsy of the left lung mass showed tissue consistent with Grade 2 neuroendocrine tumor (NET) [Figure 1]a which was immunopositive for chromogranin [Figure 1]b, synaptophysin [Figure 1]c, and cytokeratin [Figure 1]d. She was subsequently referred to the nuclear medicine department for whole-body 68Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) and 18F-fluorodeoxyglucose (FDG) PET/CT scans to detect the extent of disease. Grade-2 NET lung detected on biopsy (primary) showed positive uptake on both 68Ga-DOTANOC PET/CT [arrow, [Figure 1]e and 18F-FDG PET/CT [arrow, [Figure 1]f scans. However, multiple metastatic lesions in the liver showed no somatostatin receptor expression as evidenced by negative 68Ga-DOTANOC PET/CT [arrow, [Figure 1]g and [Figure 1]i but showed avid lesions on 18F-FDG PET/CT [arrow, [Figure 1]h and [Figure 1]j, proving it to be as poorly differentiated metastases. Similarly, another solitary metastatic lesion noted in the pancreas was positive on 68Ga-DOTANOC PET/CT scan [arrow, [Figure 1]k but showed no radiotracer uptake on 18F-FDG PET/CT [Figure 1]l, implying it to be a well-differentiated metastatic lesion. Another lesion noted in the spleen was positive on 18F-FDG PET/CT [arrow, [Figure 1]l, but no tracer uptake was observed on 68Ga-DOTANOC PET/CT scan [Figure 1]k, consistent with poorly differentiated uptake pattern. Multiple bone metastases were positive on 68Ga-DOTANOC PET/CT [arrow, [Figure 1]m but negative on 18F-FDG PET/CT scan [Figure 1]n, which implied it to be well differentiated. [Figure 1]o andpdepict the maximum intensity projection images of 68Ga-DOTANOC PET/CT [Figure 1]o and 18F-FDG PET/CT [Figure 1]p. Bronchial carcinoids are rare well-differentiated NET subclassified into typical and atypical carcinoids. Using 68Ga-DOTANOC PET/CT and 18F-FDG PET/CT scan, we can differentiate between various grades of NETs.68Ga-DOTANOC PET/CT is the initial evaluation of choice for detection of primary sites for patients with metastatic NETs of unknown origin as well as well-differentiated NETs.18F-FDG PET/CT also has an important role in managing patients with aggressive and high-grade NETs owing to its high prognostic value, and further treatment change is based on this poor differentiation of the tumor.68Ga-DOTANOC PET-CT alone at the best is helpful in delineating disease extent. The evaluation of glycolytic metabolism by 18F-FDG is potentially useful in identifying high-risk patients with aggressive neuroendocrine disease associated with a poor outcome.68-Ga DOTANOC PET/CT and 18F-FDG PET/CT have a complementary role in patients who have aggressive disease as it helps in demonstrating the total disease burden and stratify them to proper therapeutic groups. Dual-tracer imaging with 68-Ga-DOTANOC and 18-F-FDG PET-CT can have a prognostic value in metastatic NETs as positive somatostatin receptor expression with negative FDG uptake exhibits a longer progression-free survival. In such patients, somatostatin analogs can be used as first-line agent, while high FDG uptake warrants treatment with chemotherapy., In this case, splenic lesion was positive on 18-F FDG PET/CT and negative on 68Ga DOTANOC PET/CT. One must be careful in reporting splenic lesion on 68Ga-DOTANOC PET/CT as such lesions could be missed due to high physiological splenic DOTANOC uptake. This case highlights the fact that in a metastatic NET, various grades of differentiation can be present at a given point of time. Hence, imaging with 18-F-FDG PET/CT and 68-Ga-DOTANOC PET/CT can give a complete picture about the disease status and should be used in routine for better management of patients.
|Figure 1: (a-d) Grade II neuroendocrine tumor immunopositive for chromogranin, synaptophysin cytokeratin, (e and f) neuroendocrine tumor Grade II lung, both DOTANOC and fluorodeoxyglucose positive, (g and i) DOTANOC-negative liver lesions, (h and j) fluorodeoxyglucose-positive liver lesions, (k) DOTANOC-positive pancreas lesion and DOTANOC-negative spleen lesion, (l) fluorodeoxyglucose-negative pancreas lesion and fluorodeoxyglucose-positive spleen lesion, (m) DOTANOC-positive bone metastases, (n) fluorodeoxyglucose-negative bone metastases, (o) maximum intensity projection image of 68-Ga DOTANOC positron emission tomography/computed tomography, (p) maximum intensity projection image of 18-F-fluorodeoxyglucose positron emission tomography/computed tomography|
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The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
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