Living-donor Kidney Transplantation After Resection of Mixed Epithelial and Stromal Tumor: A Positive Outcome Despite...

Mixed epithelial and stromal tumor (MEST) is a benign renal neoplasm. For MEST cases requiring kidney transplantation, a waiting period is essential. However, reports on the management of MEST cases awaiting kidney transplantation are limited. We report the case of a patient with end-stage renal disease and bilateral renal pelvic tumors who was pathologically diagnosed with MEST and successfully underwent living-donor kidney transplantation without the recommended waiting period.

A 52-year-old woman had been diagnosed with mesangial proliferative glomerulonephritis 10 years earlier. Her renal function had gradually declined, and maintenance hemodialysis had been initiated 1 year before referral to us. She preferred living-donor kidney transplantation and was referred to our hospital after computed tomography at a previous institution revealed bilateral renal pelvic masses with well-defined margins and contrast enhancement. Voided urine cytology was classified as atypical urothelial cells. At the patient's request, ureteroscopic examination was not performed. For diagnostic and therapeutic purposes, robot-assisted left nephroureterectomy was performed. Histopathological examination revealed MEST, and this was confirmed via the histopathological examination of the right-sided lesion. Based on this diagnosis, right nephroureterectomy, followed by living-donor kidney transplantation up to the right iliac fossa, was performed 6 months after the left nephroureterectomy. The postoperative course was uneventful, and the patient was discharged on postoperative day 9. No evidence of recurrence or metastasis has been observed during 1 year of follow-up.

This case demonstrates that living-donor kidney transplantation without a mandatory waiting period may benefit patients with end-stage renal disease when a definitive diagnosis of MEST is established before transplantation.