Postoperative thyroid storm after radical nephrectomy for renal cell carcinoma with inferior vena cava tumor thrombus

Introduction Thyroid storm is a rare life‐threating condition. We report a case of thyroid storm after radical nephrectomy for renal cell carcinoma with inferior vena cava tumor thrombus. Case presentation A 76‐year‐old man with a left renal tumor and tumor thrombus extending into the inferior vena cava underwent left radical nephrectomy and thrombectomy. After the surgery, his postoperative course rapidly deteriorated, including central nervous system disturbance, fever, tachycardia, congestive heart failure, and hepatic manifestation. Thyroid function test revealed perioperative hyperthyroidism. Corticosteroids and inorganic iodide improved his condition, suggesting that he developed thyroid storm after surgery. He was discharged 5 months after surgery and has been free from disease recurrence for more than 2 years. Conclusion Thyroid storm after surgery is rare. However, this postoperative complication is important because it is fatal if not diagnosed and treated properly.