Q1: What abnormalities are shown on this venogram (fig 1)?

Figure 1 (see p 599) shows occlusion of the cephalic vein, with no filling of the left axillary or subclavian veins. There is extensive collateral formation. Although no thrombus is demonstrated, it was thought that this was likely to exist more centrally.

Q2: Figure 2 is from the thoracic computed tomography performed with contrast via the right arm. What abnormalities can be seen on this view?

Figure 2 (see p 599) shows that the superior vena cava is patent, and that there was no abnormality or mass in the mediastinum. There are multiple chest wall and axillary collaterals on both sides, suggesting bilateral axillary vein occlusion.

Q3: Look at fig 3. What is the diagnosis?

Figure 3 (see p 599) shows an ill defined mass in the body of the pancreas, extending around the coeliac axis. The most likely diagnosis is pancreatic cancer. This was later confirmed at postmortem examination.

Discussion

Patients with cancer often have a hypercoagulable state. The association between venous thromboembolism and malignancy is well known, a fact which is recognised on deep vein thrombosis risk assessment schemes.1

The mechanism by which thrombotic tendency is increased is complex. It is thought that tumour cells directly express procoagulants, while the host response to certain tumour cells includes the expression of similar substances, such as tissue factor (from monocytes).2

Host factors, such as age, immobility, sepsis, and drug therapy also effect clotting tendency, while tumour mass or lymphadenopathy can directly compress vessels.2

Patients with malignancy may present with a variety of clotting disorders including migratory superficial thrombophlebitis (Trousseau's syndrome), disseminated intravascular coagulation or, as in this case, with venous thrombosis.

A Swedish study in 1994 found that the incidence of cancer diagnosed within six months of venogram for suspected deep vein thrombosis was increased from 1.4% (negative) to 4.8% (positive venogram). Six months after venography the chances of being diagnosed with cancer were not significantly different between the two groups.3

Pancreatic cancer is especially strongly associated with thrombosis; it is historically linked to Trousseau's syndrome and a number of studies looking for occult malignancy in patients with idiopathic deep vein thrombosis place pancreatic cancer among the most frequently found. One study found evidence of thrombosis in 30% of patients who died from pancreatic cancer, the incidence rising to over 50% in those with tumour in the body or tail of the pancreas.3 4 However, clearly not all patients with venous thromboembolic disease have cancer, and doubt exists about the prognostic significance of an idiopathic venous thrombosis, as well as over the extent to which an occult malignancy should be pursued.

Studies place the percentage of cancers detectable after thorough history taking and examination on presentation with deep vein thrombosis between 50% and 75% of all cancers detected within six months to one year after positive venography. Analysis of cancers detected during a subsequent admission within six months of positive venography suggests that earlier diagnosis (for example, at the time of venography), and therefore more intensive investigation, would only benefit a small number of patients.3 5 6

This is because a number of the tumours were asymptomatic, and were detected at necropsy in patients who died from co-morbid conditions, and because the more strongly associated cancers, such as pancreas and liver, are generally incurable, earlier diagnosis only increasing lead time.3 5 6

This case is particularly unusual in that the axillary vein thromboses were bilateral, and had been present subclinically for some time, as evidenced by the extensive collateral formation.

There remains debate in the literature about whether certain types of thromboses have more prognostic significance than others. It may be that patients with recurrent thromboses during anticoagulation, or unusual thromboses such as the ones we have described, warrant a more aggressive search for a possible malignancy.

Final diagnosis

Bilateral axillary vein thrombosis associated with pancreatic cancer.