Histopathological examination of removed kidney allografts: Is it useful? A retrospective cohort study.

The incidence and relevance of histological findings in removed allografts is unknown. In this study, we investigated the outcome of routine histopathological examination of removed allografts. We performed a retrospective cohort study in patients with kidney graft failure ≥3 months after transplantation. In this cohort, 244 allograft nephrectomies were performed. We routinely sent removed grafts for histopathological examination. In 197 cases, a pathology report was available for analysis. In 21 of the 197 grafts, gross necrosis precluded adequate interpretation. Signs of rejection were reported in 163 of the remaining 176 allografts. Recurrences of the original disease were found in 13 cases. These were all known from prior biopsies. Relevant secondary findings were present in eight cases: renal cell carcinoma (n = 2), urothelial cell carcinoma, candida pyelonephritis (n = 2), post-transplant lymphoproliferative disease, polyomavirus inclusions, and membranous nephropathy. All conditions were diagnosed before graft nephrectomy, except for one case of papillary renal cell carcinoma of 0.8 cm. As expected, signs of acute and/or chronic rejection are the main histopathological finding in grafts that are removed after late graft failure. Unexpected secondary findings are very rare. Therefore, it is justifiable to restrict histopathological examination of removed kidney allografts to specific cases.