Urothelial Carcinoma of the Graft Kidney With Molecular Analyses: A Rare Case Report

BACKGROUNDMalignancy after transplantation is a leading cause of death in kidney transplant recipients. However, donor-derived malignancies are rarely reported. We herein report a high grade papillary urothelial carcinoma of the graft kidney, involving the graft ureter and native urinary bladder, invading one left obturator lymph node, and sparing the two native kidneys and ureters.CASE PRESENTATION62-year-old female with history of kidney transplantation more than 30 years ago, who presented with urinary tract infection, acute renal failure, and hydronephrosis of the transplant kidney. Anterograde nephrostogram showed a large filling defect in the lower pole of the transplant kidney and a filling defect in the proximal 3-4 cm of ureter. Biopsy taken from the renal pelvic mass showed a high grade urothelial carcinoma. She underwent hysterectomy, bilateral salpingo-oophorectomy, nephrectomy of native kidneys and transplant kidney, cystectomy and bilateral pelvic lymph node dissections. Histology showed a high grade papillary urothelial carcinoma of the graft kidney, involving the graft ureter, native urinary bladder and one left obturator lymph node and sparing the two native kidneys and ureters. Short tandem repeat (STR) analysis confirmed the tumor was of donor origin. The next-generation sequencing identified amplification of TERT and loss of CDKN2A/CDKN2B in the primary tumor.CONCLUSIONWhile it is known that transplant recipients have an increased risk of urothelial carcinoma compared to the general population, the lack of the well-documented risk factors, such as older age at transplantation, BK polyomavirus infection, and prolonged post-transplantation history and dissemination of the tumor in this case shed light on the de novo tumorigenesis of the graft kidney within the host microenvironment. Amplification of Telomerase reverse transcriptase (TERT) and loss of cyclin dependent kinase inhibitor 2A/2B (CDKN2A/CDKN2B) detected in the tumor by next gene sequencing suggests that they may play an important role in this case.