Pleomorfic leiomyosarcoma of the inferior vena cava

Clinical History

A 65-year-old patient with six-month history of moderate right upper quadrant abdominal pain was admitted. Due to gastric plenitude and abdominal distension without improvement after analgesia, abdominal CT was performed.

Imaging Findings

The abdominal CT (Fig. 1) showed a large mass with peripheral enhancement and central necrosis in the inferior vena cava (IVC), that originated at the confluence of the renal veins with cranial extension to the intrahepatic portion of the vena cava, causing caudate lobe growth.
A MR study (Fig. 2) was performed. It demonstrated that the lobulated mass presented partial invasion of the right renal artery, the right suprarenal gland, the right hepatic vein and the caudate lobe.
The PET-CT study excluded the presence of other foci of hypermetabolism (Fig. 3).

Discussion

Primary inferior vena cava (IVC) malignancies are uncommon, with the leiomyosarcoma, which arises from the smooth muscle cells of the vessel wall, being the most common primary neoplasm [1]. There are about 300 cases of leiomyosarcoma in the literature. It usually occurs in the fifth decade and is more frequent in women (80% of the cases).
In this malignancy it is important to determine the level of affection, which is key to the symptoms and prognosis. It is classified in three segments, as follows: infrarenal IVC (37%); middle segment, from the renal veins to the inflow of the hepatic veins (43%) and suprahepatic IVC (20%) [1, 2, 3]. The involvement of the suprarenal IVC is associated with better prognosis than the infrarenal one. The initial growth of leiomyosarcoma is intramural, but lately two-thirds of them may present extraluminal invasion and one third intraluminal growth (with risk of obstruction of IVC).
With regard to symptomatology, this sarcoma is a slow-growing tumour so it is detected only when it attains a relatively large size. Typical symptoms are weight loss, tiredness and abdominal pain. Other symptoms vary according to tumour location. When the upper segment is involved, patients may present with Budd-Chiari syndrome, cardiac arrhythmias or even pulmonary embolism. Middle section involvement is associated with nephrotic syndrome. Lower extremity oedema and deep venous thrombosis can be seen in infrarenal involvement.
To reach the diagnosis, CT and MRI are the main tools (Fig. 1 and 2), as they allow to delimit the tumour and determine the presence of invasion of adjacent tissues, as well as to exclude the presence of metastases and thrombosis. The unenhanced CT may show a lobulated mass with low attenuation central zones corresponding to necrosis and high attenuation areas due to haemorrhage. After the administration of intravenous contrast, the mass may present peripheral enhancement and central necrosis. The dilation of the cava indicates intraluminal growth tumour that differs from isolated thrombosis [4].
MRI is very useful to determine the origin and extension of the mass (Fig. 2). T1WI show an intermediate intensity mass with high signal areas corresponding to regions of haemorrhage. High intensity regions in T2WI represent necrosis spaces.
The recommended option of treatment is complete resection of the mass with reconstruction of the IVC. When it is not possible, neoadjuvant radiotherapy and chemotherapy are acceptable alternatives. The survival rate after radical tumour resection is 90- 66% at two and five years, respectively [5, 6].

Differential Diagnosis List

Final Diagnosis

Leiomyosarcoma of the inferior vena cava

URL:	https://www.eurorad.org/case/14573
DOI:	10.1594/EURORAD/CASE.14573
ISSN:	1563-4086