腎盂上皮惡性腫瘤多為過渡上皮細胞癌，原發性腎盂黏液腺癌是極為少見的原發性腎盂腫瘤，常發生於腎結石合併慢性發炎之病例。術前診斷相當困難，大多為術後病理診斷。根除性切除腎臟及輸尿管，並避免術中腫瘤細胞溢出為治療上最重要之事。

We report on a case of primary mucinous adenocarcinoma of the renal pelvis occurring in association with urolithiasis and obstructive uropathy. This 84 year-old man had suffered from abdominal distension and left flank pain for 2 years. After a series of surveys, including KUB, renal sonography, abdominal computed tomography, and Tc99m-DTPA diuretic scientigraphy, a left renal staghorn stone with non-functioning kidney was found. A left nephrectomy was performed. The kidney contained about 3000 ml of mucinous fluid with a fragile grayish-white tumor over the stone impaction site of the pelvis. The pathological report indicated mucinous adenocarcinoma. The patient was well without recurrence 15 months after the operation.