Imaging description

Pseudolipoma of the inferior vena cava refers to the apparent presence of a fatty mass in the lumen of the inferior vena cava as it passes through the diaphragm from the liver into the right atrium. The appearance is a partial volume artifact due to a layer of fat that sits above the caudate lobe next to the inferior vena cava. The cava deviates to the midline as it passes from the liver into the right atrium, and depending on local anatomy and the phase of respiration, the fat above the caudate lobe can be partial volumed in such a way that it appears to be within the vessel (Figure 1.1) [1].

Importance

Pseudolipoma of the inferior vena cava may be mistaken for a true fat-containing tumor of the inferior vena cava, such as a lipoma or liposarcoma [2], resulting in unnecessary follow-up investigations and patient anxiety.

Typical clinical scenario

Pseudolipoma of the inferior vena cava has a reported frequency of 0.5% at abdominal CT [3], but this seems far higher than I would have expected based on my clinical experience. While pseudolipoma of the inferior vena cava can be seen in anyone, it is commoner in cirrhosis, presumably because there is a greater degree of anatomic distortion and potential for partial volume artifact due to shrinkage of the liver and greater deviation of the inferior vena cava as it passes through the diaphragm in these patients (Figure 1.2).