因自發性後腹腔出血，而被診斷為腎細胞癌是非常罕見的。一位67歲之男性因為突發性右腰部疼痛及右腹腫塊而被送入急診，合併發燒及白血球過高，腹部斷層攝影發現腎周圍有一血腫且上部有密度不均性腫瘤約3 * 4 * 5公分大小，動脈攝影顯示它為無血管性腎臟腫塊，病人接受了全腎臟切除術及術後放射線治療。我們將討認論其診斷及處理。

Spontaneous retroperitoneal bleeding is a rare clinical feature of renal cell carcinoma. A 67-year old man was sent to our emergency unit because of a sudden attack of right flank pain. An abdominal mass, ever and leukocytosis were noted. Abdominal CT scan revealed a heterogenic upper pole mass and hyperdense perinephric hematoma. Arteriography showed an avascular right renal mass. Radical nephrectomy and postoperative radiotherapy were performed. No local recurrence was detected after nine months of follow-up. The diagnosis and management are discussed.