Inferior vena cava leiomyosarcoma

Inferior vena cava leiomyosarcomas are the most common type of retroperitoneal leiomyosarcoma and most common primary malignancy of the inferior vena cava.

Epidemiology

Three-quarters of cases occur in women, usually aged 40-60 years ².

Clinical presentation

When symptomatic, patients most commonly present with abdominal pain or distension ⁸. A minority of patients present with lower extremity deep venous thrombosis ⁸.

Pathology

Leiomyosarcomas of the inferior vena cava are slow-growing malignancies ¹.

EtiologyAetiology

As with other leiomyosarcomas, the histologic origin is smooth muscle cells. These are present in the vessel wall.

Location

The tumorstumours may be classified by the segment of inferior vena cava they involve, which carries implications for surgical planning and prognostication ^1,5:

• hepatic (6-24%)
• renal and suprarenal (42-50%)
• infrarenal (34-44%)

Metastatic disease occurs in up to half of cases at presentation, most commonly involving liver, followed by lung ^7,8.

Radiographic features

The tumortumour may be intraluminal, extraluminal, or both ^3-5,8. The presence of a tumortumour limited to and expanding the inferior vena cava is most likely an inferior vena cava leiomyosarcoma ¹.

CT

After identifying a retroperitoneal mass that contacts the inferior vena cava, CT features may help distinguish the origin ⁴:

• in inferior vena cava leiomyosarcomas, the inferior vena cava wall is usually imperceptible at the point of maximal contact with the mass
• in other retroperitoneal tumorstumours, the inferior vena cava is usually compressed at the perimeter of the mass (negative embedded organ sign)

On contrast-enhanced CT, if the tumortumour has an intraluminal component, it appears as a heterogeneously enhancing filling defect in the inferior vena cava ⁵.

For tumorstumours with an extraluminal component, CT-guided core needle biopsy is typically employed to obtain tissue and establish the diagnosis ¹.

Angiography

For intraluminal tumorstumours, venography may show obstruction of the inferior vena cava and presence of collateral veins ⁹. The tumortumour itself demonstrates neovascularity with marked parenchymal tumortumour blush ⁹.

For tumorstumours with predominantly intraluminal growth, transvenous biopsy is a feasible alternative to percutaneous biopsy ¹.

MRI

Signal characteristics depend on the degree of necrosis, which appears low intensity on T1-weighted images and high intensity on T2-weighted images ¹.

In contrast to bland thrombus, intraluminal leiomyosarcoma tumortumour thrombus appears iso- to hyperintense on T2-weighted images, enhances on T1-weighted postcontrast images, and expands the lumen ¹.

Treatment and prognosis

The treatment includes surgical resection, most commonly with inferior vena cava ligation and primary/patch repair ⁸. The prognosis is poor. Recurrence affects half of the patients and the 5-year survival is 33% ⁸.

The best prognosis is associated with tumorstumours in the renal and suprarenal inferior vena cava, while the worst prognosis is associated with tumorstumours in the hepatic segment of the inferior vena cava ⁵.

Differential diagnosis

Intraluminal tumortumour should be distinguished from bland thrombus (inferior vena cava thrombosis).

The differential includes other less common retroperitoneal mesenchymal neoplasms that may involve the inferior vena cava:

• angiosarcoma
• liposarcoma
• leiomyomatosis
• undifferentiated pleomorphic sarcoma

Involvement of adjacent organs should be identified, raising the more likely possibility of tumortumour thrombus extending from those organs into the inferior vena cava:

• cardiac angiosarcoma
• hepatocellular carcinoma
• adrenal cortical carcinoma
• renal cell carcinoma (most common)
• uterine leiomyosarcoma and intravenous leiomyomatosis