A 40-year-old man undergoing systemic treatment for metastatic distal rectal cancer presented with a two-week history of mild chest pain and shortness of breath. He underwent PET/CT as part of routine tumor assessment.
 
CT revealed multiple lesions consistent with metastasis and filling defects in bilateral pulmonary arteries. Fused PET/CT images revealed segments of filling defects with absolutely no FDG uptake, in contrast to others with high FDG avidity (Figure 1). This is in line with current knowledge in the literature that suggests that venous thromboemboli do not show FDG hypermetabolism. Conversely, tumor thrombi usually exhibit high FDG uptake.(1,2) Based on that, FDG-PET/CT can be a useful diagnostic imaging tool.
 

 
A diagnosis of combined thrombotic and non-thrombotic pulmonary embolism was made. The patient received anticoagulation therapy and a new line of systemic oncologic treatment.
 
Venous thromboembolism (VTE) is the third most frequent acute cardiovascular syndrome(3) and occurs in up to 10% of cancer patients.(4) Pulmonary intravascular tumor emboli are seen in about 25% of autopsies of patients with solid malignancies, although the diagnosis is rarely made before death. Because tumor embolism and VTE are difficult to distinguish, the treatment should target the underlying malignant disease and VTE at the same time.(5)
 

AUTHOR CONTRIBUTIONS
 
All of the authors equally contributed to the writing and reviewing of the manuscript.
 
CONFLICTS OF INTEREST
 
None declared.
 
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