A Rare Case of Undifferentiated High-Grade Sarcoma Masquerading as Thrombus Resulting in Acute Budd-Chiari Syndrome

Abstract

We present a rare case of Budd-Chiari Syndrome (BCS) from a high-grade undifferentiated sarcoma that invaded and obstructed the inferior vena cava (IVC), hepatic veins and right atrium. There are just 6 cases of venous undifferentiated intimal sarcomas reported in the literature. A 56-year-old Caucasian female with hypertension presented to her primary doctor with 2 weeks of abdominal bloating, abdominal pain, 10-pound weight gain and lower extremity swelling. On exam she had mild ascites, tender hepatomegaly and lower extremity edema. Liver tests were unremarkable, but abdominal ultrasound revealed both mild ascites and both IVC and hepatic vein thrombosis. She was referred to the hospital and a CT revealed extensive thrombus within the entire IVC extending into the right atrium showing a separate 5.0 cm right atrial mass, as well as thrombus extending into the right gonadal vein and the renal veins bilaterally. Imaging showed moderate ascites as well as heterogeneous liver appearance presumably related to passive congestion. A 2-D echocardiogram revealed an ejection fraction of 50-55% with IVC thrombus extending into the right atrium creating a functional tricuspid stenosis from inflow obstruction. The patient was started on a heparin drip to prevent further clot burden and transferred to a tertiary care facility for further intervention. During open heart surgery the right atrial portion of the 5.0cm mass was excised and freed from the tricuspid valve. The portion of the mass coming from the IVC was adherent to the wall of the vessel and right atrium and unresectable. Frozen section immunostains of the tumor cells revealed negative epithelial differentiation (pancytokeratin), endothelial cell markers (CD34, CD117), nerve sheath differentiation (S100), and smooth muscle actin (SMA). Additional stains were negative for actin (HHF), desmin, CD99, EMA and CAM 5.2. The histology showed that there was cell neoplasm with pleomorphism - bizarre, enlarged nuclei, high nuclear-cytoplasmic ratio and abundant mitoses indicative of undifferentiated high-grade sarcoma. The patient was referred to an oncology center for chemotherapy and the patient is doing well. Without surgical intervention this could have been misdiagnosed and treated with long term anticoagulation. This unique BCS case stresses the importance of using different image modalities such as ultrasound and CT imaging to promptly diagnosis and assess the surgical approach.2429_A Figure 1. High-grade undifferentiated sarcoma extension into the inferior vena cava (IVC) and the right atrium showing a separate 5.0 cm right atrial mass, which caused a functional tricuspid stenosis from inflow obstruction.2429_B Figure 2. CT imaging shows a massive high-grade sarcoma tumor continuously present within the dilated inferior vena cava and tumor occupation extending into the right atrium. Thrombus extends into the right gonadal vein and the renal veins bilaterally. Moderate ascites and subcutaneous edema with small bilateral pleural effusions and heterogeneous appearance to the liver presumably related to passive congestion.2429_C Figure 3. Frozen section immunostains of the tumor cells revealed negative epithelial differentiation (pancytokeratin), endothelial cell markers (CD34, CD117), nerve sheath differentiation (S100), and smooth muscle actin (SMA). Additional stains were negative for actin (HHF), desmin, CD99, EMA and CAM 5.2. The histology showed that there was cell neoplasm with pleomorphism - bizarre, enlarged nuclei, high nuclear-cytoplasmic ratio and abundant mitoses indicative of undifferentiated high-grade sarcoma.