Teaching Case

Patient with factor V leiden and protein C deficiency presents with left loin and groin pain.

Patient with known coagulopathy (Factor V leiden and Protein C deficiency). Previous history of recurrent deep vein thromboses, on life long anticoagulation but not complying. The patient presented with a three-day history of severe left loin and groin pain. On admission he was tender in left loin and clotting screen was found to be normal, as the patient was not taking his anticoagulation medication.
A CT scan of the abdomen and pelvis with IV contrast was performed in the porto-venous phase. This showed a soft tissue tubular structure to the left of the abdominal aorta, which was consistent with a thrombosed left sided inferior Vena Cava (IVC). Both common iliacs and the left renal vein drained via collateral vessels. Drainage of the lower torso and limbs was via the azygos vein which was enlarged. The intrahepatic portion of the IVC was patent.

A left sided IVC occurs in 0.2 – 0.5% of patients. It is one of a group of congenital anomalies, which include double IVC, absent IVC and retro-aortic left renal vein. A left sided IVC drains into the left renal vein and then continues as a right suprarenal IVC.
In this case it is important to identify the soft tissue mass as a thrombosed left sided IVC as this can be confused with retroperitoneal lymphadenopathy. This may lead to misdiagnosis and unnecessary biopsy of this structure as described in the literature.
Other differential diagnoses for a soft tissue mass lying to the left of the aorta include enlargement of the left hemiazygos or left gonadal vein, extra renal pelvis, post-operative herniation of bowel or stomach following splenectomy or nephrectomy and retro aortic left renal vein.