Intravascular tumor thrombus may develop in certain malignancies, including renal cell carcinoma and adrenocortical carcinoma. Renal cell carcinoma is far more common than adrenocortical carcinoma, but it can be difficult to differentiate them. In fact, they have different clinical and radiological features, as well as prognosis. Surgical planning and clinical management between them are different. We report a patient with inferior vena cava thrombus originating from adrenocortical carcinoma mimicking renal cell carcinoma clinically. Case reports and articles about adrenocortical carcinoma are reviewed.