QVI Case of the Month!

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Patient is an interesting 84 y/o female who presents with a one month history of bilateral lower extremity swelling, varicose veins and tenderness. According to the patient, the swelling is marginally gravitational with the right leg worse than the left. She denies any previous history of DVT, SVT or malignancy. She also denies history of cardiac or arterial disease. She does have a history of hypertension and angina.

Right popliteal vein                      Distal Inferior Vena Cava (IVC)   

   

                Proximal IVC                                           Proximal IVC

Proximal IVC showing flow around obstruction long (left) and cross section (right) 

  Spectral analysis of the flow in the proximal IVC (left) and the iliac vein (right)

These very high quality images demonstrate near occlusion of the inferior vena cava. Given the infrainguinal thrombus, IVC thrombosis could be a distinct possibility. This however is not the case and the differentiation is made largely by the presentation, ie: no iliac involvement. Tumor should always be considered in isolated IVC obstruction. 

Subsequent Findings:  The patient was admitted to the emergency department and anticoagulants were started; however there was no placement of a Greenfield filter due to the fact that the inferior vena cava diameter exceeds the 2.8 centimeter limitation.

Computed Axial Tomography (CAT) exams were order of the chest, abdomen and pelvis with results as dictated by the interpreting radiologist follows:  

• The CT chest exam showed no signs of pulmonary embolism and only trace pericardial and pleural effusions.  
• The CT pelvis exam with contrast revealed a small amount of free fluid in the pelvis as well as sigmoid diverticulosis without diverticulitis. No pelvic mass was identified. The CT abdominal exam with contrast revealed a markedly enlarged right kidney with no normal appearing parenchyma present with abnormal diminished enhancement. There is an abnormal soft tissue density which appears to filling the right renal vein and entering the inferior vena cava which is enlarged. Findings are highly worrisome for a tumor with intravascular extension. Enlarged retroperitoneal lymph nodes present greatest on the right, with a large soft tissue mass on the right worrisome for metastatic lymph node.

Discussion: In general the incidence of thombosis of the inferior vena cava (IVC) is relatively low compared to the incidence of deep vein thombosis (DVT). Exact incidence of IVC thombosis (IVCT) is unknown due to the variability in the clinical presentations. According to WebMD:

• The DVT rate in the United States is 60-180 cases per 100,000 population per year.  
• The frequency of IVCT in patients with DVT is 4-15%.  
• In the United States, 165,000-493,000 cases of DVT occur each year.  
• In the United States, 6600-74,000 cases of IVCT occur each year. 

Tumors  

Numerous malignancies have been associated with IVCT. Perhaps the most common  is renal cell carcinoma. The intravascular tumor extends from the renal vein and can propagate as far as the heart. The tumor can partially or completely occlude the IVC. Not all intravascular irregularities of the kidney represent tumor either. One case has been reported of a patient who underwent radical nephrectomy for presumed renal cell carcinoma and was subsequently found to have only renal vein thrombosis. Other genitourinary tumors that reportedly cause IVCT include seminomas and teratomas. 

Numerous other less common tumors reportedly involve the IVC. Intuitively, any structure that is anatomically related to the IVC can generate either direct compression or vascular invasion. Retroperitoneal leiomyosarcoma, adrenal cortical carcinoma, and renal angiomyolipoma have all been reported as presenting in association with IVCT. Even hepatic hemangioma has caused IVCT from extrinsic compression. Additionally, malignancy itself is a risk factor for DVT and thus represents a risk factor for the extension of DVT into the IVC. 

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