Leiomyosarcoma of inferior vena cava: A clinical-radiological case report

A 59-year-old female presented with a history of generalised abdominal pain, abdominal distention and loss of appetite for the last 6 months. There was no significant history of bilateral lower limb oedema or respiratory distress. Clinical examination revealed a large, firm, non-tender lump in the epigastrium and umbilical region.

Contrast-enhanced computed tomography (CECT) scan of chest and abdomen was done, showing a large heterogeneously enhancing solid lobulated mass in the retroperitoneum, predominantly on the right side. The inferior vena cava (IVC) was not visualised at the point of maximal contact between the IVC and the mass (imperceptible IVC sign) against L2–L5 vertebral bodies (Figure 1a) and superiorly evidence of IVC expansion with intraluminal tumoural extension (Figure 1b), suggesting tumour arising from infrarenal segment of IVC with superior intraluminal extension but not reaching up to hepatic veins.

There were multiple heterogeneous enhancing necrotic lesions of variable size in both lobes of liver (Figure 1c) and lung, with retroperitoneal, liver and lung lesions all showing increased uptake on PET scan (Figure 2).

Transabdominal ultrasound-guided tru-cut biopsy taken from the growth revealed a cellular spindle cell tumour with smooth muscle differentiation (Figure 3a). On immunohistochemistry (IHC), tumour cells were positive for smooth muscle actin with negative staining for DOG-1, S-100 and CD34 (Figures 3b and 3c). The negative staining excluded the possibility of differentials like gastrointestinal stromal tumour or malignant peripheral nerve sheath tumour with smooth muscle differentiation, as well as angiosarcoma. A final pathological diagnosis of leiomyosarcoma was rendered.

Background

IVC leiomyosarcoma is the most common primary malignant tumour of the IVC [1]. It grows extraluminally in approximately 62% of cases, followed by combined extra- and intraluminal growth in approximately 33% of cases and intraluminal in approximately 5% of cases [1].

Clinical Perspective

Middle aged females are most commonly affected [2]. Due to their non-specific signs and symptoms, like abdominal pain and distention, clinical diagnosis is usually delayed.

The location of the tumour within IVC decides the symptomatology, resectability and prognosis of these patients. Based on its location within the IVC, it has been divided into three segments.

• Segment I tumours – below the level of renal veins; present with pedal oedema and abdominal distention.
• Segment II tumours – between renal and hepatic veins confluence; can present with nephrotic syndrome.
• Segment III tumours – from the level of hepatic veins to right atrium; present with Budd–Chiari syndrome or pulmonary embolism.

The majority arise in Segment I (34%) or Segment II (42%) of the IVC; Segment III tumours are less common (24%) [1,2].

Imaging Perspective

Multiplanar computed tomography (CT) is ideal to delineate the true origin and extent of retroperitoneal masses. IVC leiomyosarcoma appears as a lobulated mass with heterogeneous contrast enhancement. Intraluminal extension dilates IVC, where enlargement of the vessel lumen and post-contrast enhancement of luminal filling defects favours tumour thrombus over bland thrombus [1,3].

Differentiating IVC leiomyosarcoma from primary retroperitoneal sarcoma is not always straightforward. Imperceptible caval lumen is a most useful sign for a retroperitoneal mass to be diagnosed as an IVC leiomyosarcoma with a specificity of 100% and sensitivity of 75%. On the other hand, a negative embedded IVC sign (IVC compressed to the periphery of the mass and appearing crescentic) rules out IVC mass [4].

Common sites for its metastasis are the liver, lungs, lymph nodes and bones [5].

Outcome

Surgical resection is the mainstay treatment for these tumours. Our patient was given palliative chemo-radiotherapy as she already had metastatic disease at the time of presentation, using an adriamycin-ifosfamide regime; however, the patient soon expired. They usually have a poor prognosis, with a 5-year survival rate of 33% [6].

Take Home Message

Primary IVC leiomyosarcoma is a rare malignant tumour presenting with nonspecific symptoms. Multiplanar imaging with CT is the primary modality for its diagnosis, localisation and deciding the surgical management. These tumours generally have a poor prognosis with local recurrences and metastasis on follow up. Early diagnosis and aggressive surgical resection should be the aim for improving disease-free survival of such patients.

All patient data have been completely anonymised throughout the entire manuscript and related files.