This case highlight many features of the uncommon diagnosis of IVC leiomyosarcoma. Primary inferior vena cava leiomyosarcoma is a rare malignant mesenchymal tumor which begins in the vessel wall and can have both extraluminal and intraluminal components.
In this case, there is a bulky extraluminal component with thrombosis of several caudal vessels (IVC, right iliac/thigh, left renal vein, right gonadal vein). A primary IVC leiomyosarcoma can be favored because the right adrenal gland is normal and no other structures appear to be invaded.
The next important step for the radiologist is to determine how to successfully biopsy this mass. For practices preferring CT, a posterior paraspinal approach would be fairly straightforward, ensuring that the planning images were obtained during end expiration to avoid the lower lung edge.
In our practice, we heavily favor US-guided approaches when possible as we find they are often quicker, safer, and more straightforward. One of the most important benefit for deep targets is that pressure with the ultrasound probe can decrease the needle distance up to nearly 50% for targets deeper than 10 cm 1. Thus, even though the mass appears quite deep and not feasible for an anterior approach with CT, the dynamic action of applying probe pressure can substantially decrease the depth for biopsy (as in this case).
US-technique also usually allows us to apply pressure to any potential sites of post-biopsy hemorrhage. Thus an anterior approach in the right upper abdomen splitting the inferior right hepatic lobe and hepatic flexure/2nd portion of the duodenum was performed, which is illustrated on the cine and still images. This successfully confirmed the diagnosis "Low-grade leiomyosarcoma, with concern of higher-grade tumor that was not sampled based on the size of the lesion".