COVID-19 vaccination-related [18F]FDG-avid lymph node in a patient with marginal zone B-cell lymphoma

Paulina Ziolkowska; Alicja Salyga; Monika Joks; Marek Ruchala; Rafał Czepczynski

doi:10.5603/NMR.a2023.0004

Clinical vignette

Nuclear Medicine Review 2023, 26, 52–53

DOI: 10.5603/NMR.a2023.0004

ISSN 1506–9680, e-ISSN 1644–4345

COVID-19 vaccination-related [18F]FDG-avid lymph node in a patient with marginal zone B-cell lymphoma

Paulina Ziolkowska12*

Alicja Salyga12*Monika Joks3Marek Ruchala1Rafal Czepczynski12

1Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Poznan, Poland

2Department of Nuclear Medicine, Affidea, Poznan, Poland

3Department of Haematology and Bone Marrow Transplantation, Poznan University of Medical Sciences, Poznan, Poland

*contributed equally

[Received 21 VI 2022; Accepted 4 IX 2022]

Correspondence to: Paulina Ziółkowska, Department of Endocrinology, Metabolism and Internal Medicine, Poznan University of Medical Sciences, Przybyszewskiego 49 St., 60–355 Poznan, e-mail: paulina_z1@vp.pl

This article is available in open access under Creative Common Attribution-Non-Commercial-No Derivatives 4.0 International (CC BY-NC-ND 4.0) license, allowing to download articles and share them with others as long as they credit the authors and the publisher, but without permission to change them in any way or use them commercially.

The [18F]FDG PET/CT is a crucial tool in the diagnostic process and monitoring of neoplastic diseases. Currently, during the global program of vaccination against COVID-19 and the possibility of axillary lymphadenopathy after this injection, the correct interpretation of PET/CT images is vitally significant and may create some difficulties.

We present a case of increased uptake of [18F]FDG in an axillary lymph node in a PET/CT scan performed 2 days after the Pfizer BioNTech COVID-19 vaccine in a 48-year-old patient newly diagnosed with marginal zone B-cell lymphoma.

KEY words: marginal zone B-cell lymphoma; PET/CT; COVID-19; vaccination; staging

Nucl Med Rev 2023; 26, 52–53

Case report

A 48-year-old man has been suffering from cervical lymphadenopathy, increased sweating, and weakness since September 2020, when he recovered from bilateral pneumonia (not associated with COVID-19 infection). After two non-diagnostic biopsies of the cervical and axillary lymph nodes (September and October 2020), the patient was eventually diagnosed with marginal zone lymphoma (MZL) based on a surgical biopsy of the right axillary lymph node on February 2021.

The [18F]FDG PET/CT scan was performed on 12th March 2021 for MZL staging before the treatment initiation. The reference mediastinum blood pool SUVmax was 1.8, and the liver background SUVmax was 2.6.

Coronal and axial CT scans demonstrated pathological lymph nodes located on both sides of the neck, both axillae, anterior mediastinum, and both inguinal regions. The [18F]FDG PET/CT (Fig. 1) presented mild uptake in a nodal mass of the neck, right axillary fossa, anterior mediastinum, and both inguinal regions with the SUVmax up to 2.0.

In the enlarged lymph nodes of the left axilla, the diffuse [18F]FDG uptake was also slightly increased (SUVmax 2.3), but one axillary lymph node with the size of 13 × 9 mm had higher, focal uptake of the tracer with SUVmax reaching 4.1. Furthermore, an area of mild increased [18F]FDG uptake was found in the left triceps brachii muscle (SUVmax 2.2).

Correlating it with the patient’s medical history, it was established that the second dose of the Pfizer BioNTech COVID-19 vaccination had been performed two days before the scan. We hypothesize that the significantly higher focal uptake of [18F]FDG tracer in the region of the left axilla, compared with the remaining enlarged lymph nodes was associated with an overlapping inflammatory reaction to the recent vaccine injection and MZL.

Due to the low glucose metabolism in the baseline examination (typical for MZL), PET/CT scan will not be useful for assessing the response to treatment in this case.

Conclusions

This case shows a new PET/CT image pitfall interpretation associated with the current COVID-19 pandemic vaccination program. To avoid incorrect image interpretation and inadvertent upstaging of the disease we recommend paying special attention to the recent vaccination in the patient’s medical history and taking it into account while interpreting the images. We recommend also rescheduling PET/CT scan, i.e. delaying it by several days after vaccination as long as the clinical status and management protocol allows it.

Conflict of interest

There is no conflict of interest to declare.