Renal cell carcinoma with inferior vena cava tumor thrombus initially misdiagnosed as bland thrombus due to hypercoagulable state.

Renal cell carcinoma with inferior vena cava tumor thrombus can be misdiagnosed as an inferior vena cava thrombosis if not evaluated carefully with imaging. We describe a case of renal cell carcinoma with inferior vena cava tumor thrombus that was initially misdiagnosed as an inferior vena cava thrombosis due to a possible hypercoagulable state. After 7 months of anticoagulation therapy with no improvement, a right radical nephrectomy and thrombectomy was performed without cardiopulmonary bypass, and a diagnosis of papillary renal cell carcinoma with a level-IIId tumor thrombus was confirmed with no presence of a bland thrombus. We demonstrate the complexity of identifying and treating renal cell carcinoma with venous tumor thrombus and the importance of differentiating between a malignant thrombus and a bland thrombus.