Retroperitoneal tumors are rare, constituting less than 0.1% of malignant tumors, most of which are sarcomas. Among tumors originating from blood vessels, the majority are leiomyosarcomas, with venous involvement being five times more common than arterial involvement (1). Leiomyosarcoma of the vena cava is extremely rare, with only 200 cases reported worldwide since 1871 (2). This mesenchymal tumor originates from the smooth muscle cells of the vena cava (3). Surgical treatment is the only curative option (4). In this article, we aim to present a rare case of a vena cava tumor treated in our clinic, accompanied by a review of the literature.
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Case
A 55-year-old female patient was referred to our clinic with a preliminary diagnosis of an intra-abdominal mass. She had been experiencing fatigue and subjective abdominal pain for a year but had no other complaints. Ultrasonography (USG) revealed a mass localized in the right upper quadrant, indistinguishable from the liver. Subsequent abdominal computed tomography (CT) identified a tumor mass measuring 90x80 mm, located beneath the liver, compressing the vena cava, and displacing the duodenum laterally.
Further evaluation for a suspected vena cava tumor included thoracic CT for metastasis assessment and dynamic contrast-enhanced abdominal magnetic resonance imaging (MRI) to study the mass's structure. Thoracic CT was normal, and MRI revealed a well-contoured hypodense lesion localized at the lower border of the liver's right lobe, displacing the gallbladder laterally and closely associated with the hepatic artery and portal vein without compression. The lesion compressed the vena cava and renal veins.
No thrombus or intraluminal mass was identified in any imaging studies. All preoperative biochemical, serological, tumor marker, and endoscopic evaluations were normal.
During surgery, the mass was found to be well-demarcated, not involving surrounding tissues, and measured 12x10 cm. It was localized at the junction of the right and left renal veins, originating from the vena cava. Adhesions on the mass were dissected to expose the vena cava, revealing a segment 6 cm long and 3 cm wide that was involved by the tumor.
Both renal veins and the proximal and distal vena cava segments were dissected and suspended for hemorrhage control. Intraoperative evaluation suggested that the vena cava could not be closed primarily, necessitating the use of a synthetic vascular graft for repair. The vena cava was partially obstructed using a Satinsky clamp, and total tumor excision and partial vena cava resection were performed while preserving the renal veins. The vena cava was then reconstructed using a synthetic graft with 4/0 Prolene sutures.
The patient experienced no postoperative complications and was treated with low molecular weight heparin for anticoagulation. Doppler USG performed on postoperative days 1 and 2 confirmed normal flow in the vena cava and renal veins. The patient was discharged in good condition on the fifth day and remained recurrence-free at the 18-month follow-up.
The resected specimen measured 14x10x7 cm, weighed 540 g, and appeared encapsulated with a gray-yellow elastic consistency (Figure 4a). Sectioning revealed a cream-colored, fibrous structure with nodular areas. Microscopic examination showed malignant tumor infiltration with spindle-shaped cells exhibiting pleomorphism, hyperchromatic nuclei, and eosinophilic cytoplasm arranged in intersecting fascicles.
Immunohistochemical analysis revealed positive staining for SMA (smooth muscle actin), caldesmon, and desmin (Figure 4d). Focal staining was observed with S-100, but no staining occurred with cytokeratin, myoglobin, CD34, or MYO D1. The Ki-67 proliferation index was 25%. These findings suggested a spindle-cell sarcomatous malignant tumor, most likely (moderately differentiated) leiomyosarcoma. Necrosis was observed in 5% of the tumor, which was confined by a pseudocapsule and contiguous with the surgical margin in one area.
Discussion
Vena cava tumors are exceedingly rare, with most literature comprising case reports, short series, or reviews. Tumor localization is critical for determining surgical techniques. In the literature, vena cava tumor localization is classified into three types: lesions below the renal veins (type I), tumors between the renal and hepatic veins (type II), and those above the hepatic veins (type III) (5). Our case was classified as a type II vena cava tumor.
Dynamic contrast-enhanced abdominal CT and MRI are usually sufficient for diagnosis, with venography used in uncertain cases. PET can be utilized for staging (6).
The surgical technique varies with tumor size. Some cases require segmental vena cava resection, while others, like ours, allow resection with patch repair while preserving the vena cava. Advanced cases may necessitate concurrent resection of the right kidney, duodenum, or adrenal gland (3).
Some patients present with distant metastases, underscoring the importance of systemic evaluation, particularly for the lungs, to avoid unnecessary surgery (6).
Prognosis is poor, with untreated cases surviving 3–6 months on average. Five-year survival rates after curative resection are 30–50%, and 10-year survival rates are 7–10% (6). Local recurrence is common, reported in 30–50% of cases within five years. Postoperative radiotherapy is recommended, although the role of adjuvant chemoradiotherapy remains unclear. Some studies suggest preoperative radiotherapy benefits, but consensus is lacking (7,8).
Long-term anticoagulation is necessary for patients with synthetic grafts to maintain vena cava continuity. Low molecular weight heparin or oral anticoagulants are recommended (9).
Anticipating vascular challenges in this region is critical. Preparing vascular grafts preoperatively, involving vascular surgery teams, and preventing intraoperative complications are essential. Patients with retroperitoneal masses closely associated with vessels or direct vena cava tumors should be referred to specialized centers.
