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Tumour Embolism in a Case of Osteogenic Sarcoma Detected on 18F-FDG PET/CT
*Corresponding author: Dr. Nihit Mhatre, Department of Nuclear Medicine, Jupiter Hospital, Pune, 411045, Maharashtra, India. drnihit14@gmail.com
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Received: ,
Accepted: ,
How to cite this article: Mhatre N, Venkatachalam M, Shukla V, Chaturvedi M. Tumour Embolism in a Case of Osteogenic Sarcoma Detected on 18F-FDG PET/CT. Indian J Nucl Med. 2026;41:256-7. doi: 10.25259/IJNM_60_23
A 42-year-old male presented with a rapidly enlarging, painful swelling in the left distal thigh. Imaging and biopsy confirmed a high-grade osteogenic sarcoma. Baseline metastatic evaluation with 99mTc-Technetium -99m Methylene Diphosphonate (99mTc-MDP) bone scan was negative, while Computed Tomography (CT) thorax revealed two pulmonary nodules suspicious for metastases. For further staging, an 18F-Fluorodeoxyglucose Positron Emission Tomography /Computed Tomography (FDG PET/CT) demonstrated a large hypermetabolic distal femoral mass with necrotic changes
Maximum Standardised Uptake Value (SUVmax) max ~8.5 and mildly FDG-avid pulmonary nodules [Fig 1]. Additionally, a focal FDG-avid filling defect was identified in the inferior vena cava (IVC) just above the iliac confluence (SUV max ~5.1), suggestive of tumour thrombus [Fig 2]. No contiguous venous extension from the primary tumour was seen, favouring a rare non-contiguous tumour thromboembolism. Osteosarcoma most commonly metastasises to the lungs and bones, while vascular involvement is uncommon and usually occurs by direct extension.[1,2] Detection of a discrete FDG-avid intravascular lesion distant from the primary site is rare and may be underrecognised on conventional imaging. 18F-FDG PET/CT aids in identifying such metabolically active lesions and in differentiating tumour thrombus from bland thrombus.[3] Recognition of tumour embolism is clinically relevant, as it may influence staging, guide management, and help anticipate potential complications such as further embolisation.[4-6] This case highlights the added value of whole-body PET/CT in detecting unusual metastatic patterns and vascular involvement in osteosarcoma.
- (a) Three-dimensional map (Maximum intensity projection) of the whole body FDG PET/CT. (b-c) Fused PET/CT and CT images of the primary left femoral mass with increased FDG uptake, with central necrotic changes and marked periosteal reaction (yellow arrows). (de) Fused PET/CT and CT images of two nodular lung metastases with low-grade FDG uptake (white arrows). FDG: Fluorodeoxyglucose; PET/CT: Positron emission tomography/computed tomography
- (a-d) Fused PET/CT and CT images of a focal FDG avid filling defect in the proximal inferior vena cava suggestive of a tumour thrombus (blue arrows). FDG: Fluorodeoxyglucose; PET/CT: Positron emission tomography/computed tomography
Author contributions:
NM: Conceptualisation, writing original draft, review and editing; MV and VS: Review and editing; MC: Investigation, review and editing
Ethical approval:
Institutional Review Board approval is not required.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given consent for their images and other clinical information to be reported in the journal. The patient understand that the patient’s names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Conflicts of interest:
There are no conflicts of interest.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript, and no images were manipulated using AI.
Financial support and sponsorship: Nil.
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