CASE 13693 Published on 21.11.2016

Recurrent malignant caval thrombosis: value of diffusion-weighted MRI


Uroradiology & genital male imaging

Case Type

Clinical Cases


Tonolini Massimo, MD.

"Luigi Sacco" University Hospital,
Radiology Department;
Via G.B. Grassi 74
20157 Milan, Italy;

77 years, male

Area of Interest Veins / Vena cava ; Imaging Technique CT, MR
Clinical History
Asymptomatic elderly male patient with previous radical right nephrectomy for G2 pT3Nb clear-cell renal carcinoma including ipsilateral adrenalectomy and removal of renal vein thrombus one year earlier, undergoing follow-up imaging. Past history also included lung tuberculosis and removal of colonic polyps. Laboratory assays revealed proteinuria.
Imaging Findings
With sufficient renal function, at an outside facility CT (Fig.1) was acquired in the portal venous phase and compared to previous postoperative study (not shown). The infrahepatic inferior vena cava (IVC) showed the appearance of a near-complete filling defect which measured 3.5 cm craniocaudal diameter and caused minimal vessel dilatation. Local recurrence in the nephrectomy bed, adenopathies and distant metastases were excluded.
A month later, the uro-oncologist referred the patient to our department; meanwhile, renal function had worsened (estimated glomerular filtration rate 30 ml/sec). Unenhanced MRI (Fig.2) confirmed mild dilatation of the infrahepatic IVC from thrombus with heterogeneous, moderately high T2- and low-to-intermediate T1-weighted signal intensity with speckled hypersignal foci. Without use of intravenous gadolinium contrast, the marked hyperintense signal of the IVC thrombus on diffusion-weighted images with corresponding hypointensity on apparent diffusion coefficient (ADC) maps allowed diagnosis of malignant thrombus from renal carcinoma recurrence, which was treated with sunitinib.
Abdominal venous thrombosis is encountered in 1.3% of all patients undergoing cross-sectional imaging for oncologic follow-up, and involves the inferior vena cava (IVC), renal veins and portal system in descending order of frequency; the prevalence is higher in patients treated for renal cell carcinoma (RCC) compared to primary retroperitoneal, hepatocellular and metastatic liver tumours. The key issue is differentiating neoplastic versus bland (benign) thrombosis: the latter is the leading cause of IVC obstruction in the general population, typically originates in the lower extremities and pelvic veins and is often associated with risk factors such as immobility, trauma, hypercoagulability, abdomino-pelvic inflammation or sepsis [1-4].
Conversely, venous extension of RCC represents a key staging and prognostic factor, may affect the ipsilateral renal vein (50%, stage T3a), subdiaphragmatic (4 10%, T3b) or supradiaphragmatic IVC and right atrium (1%, T3c) and affects surgical management [5-7]. In the preoperative setting, CT and MRI have high (>85%) sensitivity and specificity for detecting and assessing extent of RCC venous invasion. Malignancy of thrombus is suggested by continuity with the primary tumour, dilatation of the IVC lumen, and presence of enhancing vessels indicating thrombus neovascularity [2-4, 7].
After nephrectomy, RCC recurrence is common within the first 3 years, is strongly influenced by tumour stage and histologic grade, may involve the surgical bed, lymph nodes, and distant sites (particularly bones, lungs, liver and brain), and is associated with a dismal prognosis. Conversely, the isolated recurrence of RCC in the IVC following surgical resection is very rare (incidence below 2%), may manifest with signs or symptoms of venous obstruction such as lower limb pain and tenderness, dilated superficial abdominal wall veins, proteinuria or pulmonary thromboembolism; however, slow growing malignant thrombi are often (40% of cases) asymptomatic and detected by imaging [5, 7-11].
As this case demonstrates, similarly to portal vein thrombosis, diffusion-weighted MRI with quantification of apparent diffusion coefficients (ADC) may confidently differentiate bland from malignant IVC thrombosis without use of intravenous contrast. The former thrombi are iso to hypointense on T2-weighted images and do not show restricted diffusion; conversely malignant ones show heterogeneous tumour-like signal and low ADC values similar to those observed in RCC compared to normal renal tissue and oncocytomas [1, 12-14].
Treatment of locally recurrent RCC in the IVC is challenging: surgical thrombectomy with partial IVC resection and defect reconstruction has been attempted in some patients; alternatively systemic chemotherapy may offer some benefit in terms of survival [11].
Differential Diagnosis List
Neoplastic caval thrombus from renal carcinoma recurrence
Artefactual filling defect (pseudothrombus)
Bland thrombosis
Leiomyosarcoma of the inferior vena cava
Local neoplastic recurrence in the nephrectomy bed
Final Diagnosis
Neoplastic caval thrombus from renal carcinoma recurrence
Case information
DOI: 10.1594/EURORAD/CASE.13693
ISSN: 1563-4086