Right supernumerary kidney with urothelial carcinoma: A case report

A supernumerary kidney is an extremely rare renal anomaly. Currently, <100 cases are reported in the literature. There are only 2 right unilateral supernumerary kidneys reported in the literature thus far, but no confirmed cases of urothelial carcinoma in supernumerary kidneys. We report a case of a right supernumerary with urothelial carcinoma, which is, to the best of our knowledge, reported for the first time.

A 73-year-old female patient presented with intermittent, painless, whole course and gross hematuria for about 3 months. Her physical and laboratory examinations did not reveal any significant findings except positive occult blood in routine urine examination. Contrast-enhanced spiral computed tomography revealed a dysplastic supernumerary kidney under the normal right kidney.

The ureteroscopy showed that the ureter was Y-shaped in the middle part. The medial ureter led to a normal kidney. The lateral ureter was just 2 cm and led to a small cavity in which there was a mass whose biopsy showed urothelial carcinoma. The patient was subsequently diagnosed with a right supernumerary kidney with urothelial carcinoma.

Nephroureterectomy, including the right normal and supernumerary kidneys, and partial cystectomy by laparoscopy were performed after the ureteroscopy. The patient then received 6 cycles of gemcitabine and cisplatin regimen chemotherapy and regular intravesical epirubicin chemotherapy.

No recurrence or metastasis was found on follow-up computed tomography performed 13 months postoperatively.

A supernumerary kidney is an extremely rare renal anomaly. Malignancy can occur in supernumerary kidneys.