Simple Nephrectomy for Non-Functioning Kidney: An Institutional Experience with Non-Neoplastic and Incidentally Detected Neoplastic Lesions

<i>Introduction.</i> Chronic kidney diseases are attributed to a variety of etiologies, including diabetes mellitus, hypertension, vascular diseases, cystic kidney diseases, chronic tubulo-interstitial diseases, chronic pyelonephritis, and glomerular diseases. Simple nephrectomy is indicated when the loss of renal function in a unilateral non-functional kidney is permanent in a persistently symptomatic patient. Uncommonly, a non-functional kidney may develop neoplasm unsuspected pre-operatively and be diagnosed only during histopathological examination of nephrectomy specimen. <i>Material and methods.</i> We examined 275 simple nephrectomies performed between 2019 and 2024 in patients with non-functional kidneys confirmed by DMSA scan. All nephrectomies done for diagnosed or even suspected tumors by pre-operative imaging were excluded from the study. <i>Results.</i> Chronic pyelonephritis (79.3%) was the most common histopathological diagnosis, followed by xanthogranulomatous pyelonephritis (8.7%) and granulomatous pyelonephritis (5.4%). In five (1.8%) patients, microscopy revealed non-specific chronic interstitial inflammation and interstitial fibrosis. One patient (0.4%) was diagnosed with large solitary pyelogenic cyst and renal nocardiosis. Eleven patients (4%) were diagnosed with neoplasms. Clear cell renal cell carcinoma was the most common diagnosis (27.2%), followed by urothelial carcinomas of renal pelvis (18.2%), one patient each of collecting duct carcinoma, squamous cell carcinoma of renal pelvis, and multilocular cystic renal neoplasm of low malignant potential. Three patients had papillary adenomas. <i>Conclusion.</i> Diligent histopathological examination of simple nephrectomy is crucial in establishing the final diagnosis with important further therapeutic implications. This is especially important in neoplastic pathologies developing in non-functional kidneys that may rarely be unsuspected by pre-operative imaging and diagnosed only during histopathological evaluation.