Intimal sarcoma of the inferior vena cava with extension to the right atrium, bilateral renal vasculature, and bilateral venae iliaca communis, accompanied by severe thrombocytopenia.

A 66-year-old Asian female diagnosed with an occupied mass of the inferior vena cava (IVC) case with extension to the right atrium, bilateral renal vasculature, and venae iliaca communis, which caused severe thrombocytopenia and severe liver and kidney dysfunction. The postoperative pathological diagnosis was high-grade undifferentiated intimal sarcoma. There have been less than 10 cases of venous undifferentiated intimal sarcomas reported in the literature, three of which occurred in the IVC. Unfortunately, the patient died of multiple organ failure in the intensive care unit postoperatively.