Right atrial extension of inferior vena cava thrombosis after microwave ablation of colorectal liver metastasis: a case report

Thromboembolic complications after microwave ablation of colorectal liver metastases are rare but can be life-threatening. We report a 43-year-old woman with advanced colon adenocarcinoma and a synchronous right hepatic lobe metastasis who underwent laparoscopic right hemicolectomy combined with microwave ablation. Sixteen days post-procedure, imaging revealed an inferior vena cava thrombus extending into the right atrium. Despite therapeutic anticoagulation with low-molecular-weight heparin and warfarin, the right atrial thrombus paradoxically increased in size. Anticoagulation alone failed, and the patient successfully underwent thoracoscopic cardiac thrombectomy. Microwave ablation of liver metastases adjacent to the inferior vena cava or its major hepatic vein can trigger thrombosis with paradoxical upward extension to the right atrium, even during therapeutic anticoagulation. When anticoagulation fails, surgical thrombectomy may be lifesaving. This case underscores the need for high clinical vigilance for thromboembolic events after microwave ablation in high-risk anatomical settings and highlights the importance of a multidisciplinary management approach.