Answer of September 2024

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Clinical History:

A 57-year-old woman attended the radiology department for a follow-up computed tomography (CT) study. She had sigmoid colectomy performed 5 years ago for stage I colon cancer. Her serum carcinoembryonic antigen (CEA) level was normal.

Non-contrast CT - axial

CT with contrast - axial

CT with contrast - coronal

CT with contrast - sagittal

DIAGNOSIS:

IVC leiomyosarcoma

DISCUSSION:

IVC leiomyosarcoma is a malignant sarcomatous growth which arises from the smooth muscle cells present in the vessel wall. While it is the most common primary malignancy of the IVC, it is a rare disease entity with less than 300 reported cases in the literature. Over two-thirds of the patients are women, and most are diagnosed in their 5th to 6th decade of life.

IVC leiomyosarcoma can be classified into three groups depending on its location of involvement, which are upper-segment from right atrium to hepatic veins, middle-segment from hepatic veins to renal veins, and lower-segment caudally from infrarenal segment. It most frequently occurs from the level of diaphragm to renal veins, although entire IVC involvement has been reported. Depending on the location, IVC leiomyosarcoma may present with different symptoms, such as Budd Chiari syndrome in upper-segment, nephrotic syndrome in middle-segment and lower limb oedema in lower-segment. Other common manifestations include abdominal pain, abdominal mass, weight loss, nausea and vomiting. Metastasis of IVC leiomyosarcoma occurs in about half of the cases, such as to the liver and the lungs.

Contrast CT plays an important diagnostic role. In patients with IVC leiomyosarcomas, as illustrated in this case, there is an enhancing mass abutting the IVC vessel wall. The mass is usually indistinguishable from the vessel wall at the area of maximal contact. The IVC is often expanded at the level of the mass. In contrast, for other retroperitoneal tumors, the IVC is usually compressed, reflecting its extra-luminal origin. In addition, the presence of contrast enhancement of the filling defect in the IVC excludes bland thrombosis. CT is also helpful to characterize the lesion as intraluminal, extraluminal or both intra- and extra-luminal. For tumors with extra-luminal component, ultrasound- or CT-guided biopsy is often performed for histopathological confirmation. Whereas for intraluminal IVC leiomyosarcoma, transvenous approach can be considered, though it is considered technically challenging. On magnetic resonance imaging, IVC leiomyosarcoma is typically T1-weighted hypointense and T2-weighted hyperintense, especially those with higher degree of cystic necrosis. Similar to contrast CT, heterogeneous contrast enhancement of the tumor is expected.

IVC leiomyosarcoma can be treated by means of surgical resection, usually with IVC ligation, and primary or patch repair. Unfortunately, the prognosis is poor with 5-year survival of about one-third. Tumor recurrence also occurs in about half of the patients.