Long-Term Outcome of Kidney Transplant Patients from Rural Farming Areas with Balkan Nephropathy-A Single-Centre Report.

Background: Balkan nephropathy (BEN) is an environmental form of aristolochic acid nephropathy (AAN) strongly associated with upper urinary tract urothelial carcinoma (UTUC). Clinical diagnosis remains challenging, and misclassification is frequent. The study reassessed BEN diagnoses in kidney transplant recipients from rural farming areas who did not undergo prophylactic bilateral nephroureterectomy and evaluated post-transplant outcomes. Methods: In this retrospective single-centre study, we analysed 12 kidney transplant recipients from rural Balkan farming regions. BEN diagnoses were reevaluated according to international consensus criteria. Key endpoints included patient and graft survival, post-transplant clinical course, and UTUC characteristics. Results: Upon reassessment, three of the six patients initially diagnosed with BEN were reclassified as having BEN. Among the remaining six patients, four were reclassified as having sporadic BEN. Overall, only 33% of patients had a diagnosis concordant with their admission records. During a median follow-up of 6.8 years (IQR 2.1-15.8), UTUC developed in seven out of 12 patients. The UTUC cases were predominantly high-grade and multifocal, and they were identified as the leading cause of death. Five-year patient and graft survival rates were 71% and 100%, respectively. Conclusions: BEN is frequently misdiagnosed or misclassified in kidney transplant candidates from rural farming areas. Despite excellent graft survival, the high incidence of post-transplant urothelial carcinoma underscores the necessity of accurate diagnosis and the consideration of prophylactic bilateral nephroureterectomy. Lifelong intensive surveillance is essential not only for patients from established BEN regions but also for individuals from other rural farming areas at risk for sporadic BEN.