Man with history of thyroid carcinoma.

Our appreciation is extended to Dr. Parin Bhayani, Indiana University Department of Radiology, for contributing this case.

Click these images to enlarge them.



Which choice is most appropriate?

Anterior mediastinal mass.Pulmonary embolism.Dissection.Venous thrombosis.Esophageal mass.

Man with history of thyroid carcinoma.

Here are images providing PET / CT correlation. Click to enlarge.


Anaplastic thyroid carcinoma and total thyroidectomy. Patient has facial and neck swelling.


What is unusual about the findings, and what are the implications? (Revealed on next page of the case).

Man with history of thyroid carcinoma.

Differential diagnosis:

• Tumor thrombus
• Bland (benign) thrombus
• Septic thrombus

Man with history of thyroid carcinoma.

Key points: 

• Two types of intravascular thrombi
  • Venous thrombosis or thromboembolism (benign thrombus)
    • Etiology - Virchow's triad
    • Occurs frequently, common in patients with malignancy
    • Consists of platelets, macrophages and fibrin mesh
  • Tumor thrombus
    • Rare complication of solid cancers – most frequently renal cell and hepatocellular carcinoma
    • Direct extension of tumor into the vasculature
    • Consists of actual tumor cells
• Differentiating between these two is important because it can change patient staging and subsequent management
• Several small scale studies have demonstrated that PET/CT is useful in differentiating between the two
  • Bland thrombus can take up FDG but is usually mild with an SUV max < 3.5
  • Tumor thrombus is very FDG-avid and usually has SUV max > 5

References: 

1. Sharma P, et al. F-FDG PET-CT in the Diagnosis of Tumor Thrombus: Can it be Differentiated from Benign Thrombus. Nuclear Medicine Communications 2011, 32:782-788.
2. Gurney, J. SVC Syndrome. StatDx, Accessed 10/22/2011.

Man with history of thyroid carcinoma.

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