Teaching Case

52-years-old female underwent US exam referring long time lumbar pain and weight loss of 12 kg in the last year. The US exam showed solid hypoechoic cephalopancreatic mass of 5 cm reaching the duodenum. Then she underwent CT, MRI exams and final trans-caval biopsy in the angiography suite.

The CT showed: solid peripancreatic hypovascular mass of 4 cm with necrotic core (Fig.1, 2) and periferic enhancement in the latest phases (Fig.3, 4). The mass infiltrates inferior vena cava, bilateral renal veins and portal vein (Fig.3). There are enlarged lymph nodes nearby (Fig.2). There are also two pericentimetric hepatic hypovascular lesions of uncertain nature. The MRI confirmed the presence of solid lobulated hypovascular mass (Fig. 5) with high DWI (diffusion-weighted imaging) restriction signal(Fig.6, 7). The lesion is posterior to uncinated process of pancreas, centrated to retrohepatic part of inferior vena cava (Fig.1, 2). It suboccludes portal and it reaches the aortic wall (Fig. 1, 2, 3). The smallest of the two hypovascular hepatic lesions, showed by CT, is compatible with metastasis. In the angiographic suite a biopsy was performed in the site of intraluminal defect of inferior vena cava using a right venous femoral access (Fig.8, 9, 10).

Retroperitoneal masses are a huge group of benign and malignant masses. They can originate by connective, adipose, muscular, vascular, neuronal tissues or embryonic remnants. They are slow-growing malignancies and they give late symptoms. Clinical and laboratoristic findings are aspecific. Radiographic imaging is necessary to find the location of primitive lesion and for oncologic staging but it does not give a diagnosis of nature. Biopsy is mandatory to find the nature of the lesion [1].

Inferior vena cava leiomyosarcomas represent the second most common type of retroperitoneal masses after liposarcomas. They are also the most common primary malignancy of inferior vena cava. Three-quarters of cases occur in women (40-60 years) [2], generally asymptomatic because of their slow-growing tendencies. When symptomatic, aspecific abdominal pain or distension are present [3]. Leiomyosarcomas originate from smooth muscle cells, that are present in vessel wall. At the time of diagnosis, half of inferior vena cava leiomyosarcomas are metastatic.

On contrast-enhanced CT the tumor appears as a heterogeneously enhancing filling defect in the inferior vena cava [4]. Pathognomonic findings are large necrotic core, larger than other retroperitoneal masses, and inferior vena cava intra- and extra-luminal growth. Venography performed in the angiography suite shows obstruction of the inferior vena cava or intraluminal filling defect. Trans-venous biopsy is a feasible alternative to percutaneous biopsy [1]. In MRI signal characteristics vary on the degree of necrosis, that has low intensity on T1-weighted images and high intensity on T2-weighted images [1].

Treatment includes surgical resection, with inferior vena cava ligation and primary/patch repair [3]. The prognosis remains poor. Recurrence represents half of the patients and 5-year survival is 33% [3].

Better prognosis is associated with renal and suprarenal inferior vena cava tumors. The worst prognosis is associated with lesions in the hepatic part of inferior vena cava [4].

Take home message

When at radiological imaging found a retroperitoneal mass involving inferior vena cava, it is necessary to associate radiographic features with biopsy to reach diagnosis [1] [5]. The trans-caval bioptic approach one is simple, feasible and valid alternative to the percutaneous approach.