Spontaneous caval tumor thrombus necrosis and regression of pulmonary lesions in renal cell cancer

Idiopathic regression of metastases is one of the features of the unpredictable behaviour of renal cell carcinoma. We report a patient with pulmonary metastases and a tumor thrombus in the inferior vena cava with spontaneous regression of the lung lesions and necrosis of the thrombus before any therapy was instituted.