Translate this page into:
Painted with the Same Brush: Identical PET/CT Scans in DLBCL Using Unrelated Tracers
Address for correspondence: Dr. Dhanapathi Halanaik, Department of Nuclear Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India. E-mail: dhanapathih@gmail.com
-
Received: ,
Accepted: ,
This article was originally published by Wolters Kluwer - Medknow and was migrated to Scientific Scholar after the change of Publisher.
Abstract
We report a unique case of a patient with histopathologically proven diffuse large B-cell lymphoma (DLBCL) who underwent both 18F-fluorodeoxyglucose and 68Ga-Pentixafor positron emission tomography/computed tomography scans. The imaging findings showed an identical pattern of radiotracer uptake in disease-involved sites, including lymph nodes and extranodal sites. Despite the tracers having unrelated mechanisms, this concordance in imaging underscores the potential for complementary roles in disease staging, response evaluation, and theranostic applications in DLBCL cases exhibiting CXCR4 expression.
Keywords
18F-fluorodeoxyglucose
68Ga-pentixafor
CXCR4
diffuse large B-cell lymphoma
positron emission tomography/computed tomography
theranostics
A 35-year-old male has been diagnosed with diffuse large B-cell lymphoma (DLBCL). He presents with bilateral leg swelling, generalized lymphadenopathy, and B symptoms. The initial evaluation included a biopsy from the left supraclavicular lymph node, which confirmed a diagnosis of high-grade B-cell non-Hodgkin lymphoma, germinal center subtype, and positive for CD79a. His serum lactate dehydrogenase levels were elevated at 567 IU/L, whereas other blood parameters remained normal.
Baseline staging using 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) revealed extensive disease on both sides of the diaphragm, involving multiple nodal and extranodal sites [Figure 1a]. The high disease burden resulted in a significant reduction in physiological FDG uptake in various organs, including the brain, a phenomenon known as the tumor sink effect.[1]
In addition, as the part of a prospective study, the patient underwent 68Ga-pentixafor PET/CT. This imaging showed a similar uptake pattern in disease-involved sites but with minimal physiological background activity [Figure 1b]. Notably, FDG uptake in the left proximal thigh, suggesting inflammation, was absent on pentixafor imaging. Both tracers demonstrated consistent uptake in bone marrow lesions [Figure 2].
While 18F-FDG PET/CT remains the gold standard for staging and assessing metabolic activity, 68Ga-pentixafor PET/CT provides improved characterization of the tumor microenvironment by targeting CXCR4, a receptor that is overexpressed in DLBCL.[2345] This suggests potential applications in disease staging and theranostics, particularly for CXCR4-targeted radionuclide therapy in refractory cases. However, further clinical studies are needed to validate its effectiveness in routine clinical practice.[67]
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Conflicts of interest
There are no conflicts of interest.
Nil.
References
- Influence of metabolic tumor burden on reference tissues’ standardized uptake values in 18F-FDG PET/CT sequential imaging. Egypt J Radiol Nucl Med. 2023;54:195. [doi: 10.1186/s43055-023-01140-8]
- [Google Scholar]
- Recommendations for Initial Evaluation, Staging, and Response Assessment of Hodgkin and Non-Hodgkin Lymphoma: The Lugano Classification. J Clin Oncol. 2014;32:3059-67.
- [Google Scholar]
- A review on CXCR4/CXCL12 axis in oncology: No place to hide. Eur J Cancer. 2013;49:219-30.
- [Google Scholar]
- C-X-C chemokine receptor 4 in diffuse large B cell lymphoma: Achievements and challenges. Acta Haematol. 2019;142:64-70.
- [Google Scholar]
- FDG PET/CT of extranodal involvement in non-Hodgkin lymphoma and Hodgkin disease. Radiographics. 2010;30:269-91.
- [Google Scholar]
- PET of CXCR4 expression by a (68) Ga-labeled highly specific targeted contrast agent. J Nucl Med. 2011;52:1803-10.
- [Google Scholar]
- Feasibility of CXCR4-directed radioligand therapy in advanced diffuse large B-cell lymphoma. J Nucl Med. 2019;60:60-4.
- [Google Scholar]