Simple renal cyst and glomerulopathy: is there a connection?

BACKGROUND: Simple renal cysts are quite common in the general population and are often accompanied by a decrease in the glomerular filtration rate, which may be linked to latent glomerulopathies. Delayed diagnosis of glomerular damage inevitably leads to the progression of chronic kidney disease. AIM: To assess the likelihood of hidden glomerular lesions in patients with simple renal cysts. MATERIALS AND METHODS: The study involved a group of 78 patients, including 29 men (37%) and 49 women (63%), with renal cysts of classes I and II according to the Bosniak classification (2019). An exclusion criterion for the study was a history of nephrological diseases. The mean age of the patients was 59.11±1.47 years, and the mean cyst size was 7.19±1.98 cm. All patients underwent laparoscopic excision of the renal cyst walls. Intraoperatively, a renal parenchymal biopsy was performed under visual control, and the nephrobiopsy specimens were examined using light microscopy, immunofluorescence analysis, and electron microscopy. RESULTS: Based on the analysis of 234 nephrobiopsy specimens, morphological signs of glomerulopathy were identified in 20.5% of patients, including diabetic nephropathy (37.5%), focal segmental glomerulosclerosis (31.3%), mesangioproliferative IgA glomerulonephritis and hypertensive nephropathy (12.5% each), and thin basement membrane disease (6.2%). Patients with glomerulopathy exhibited reduced glomerular filtration rate and increased creatinine and uric acid levels in the serum. Moreover, proteinuria and leukocyturia were more frequently observed in the common urinalysis of this group of patients. CONCLUSIONS: The combination of a renal cyst, changes in urinalysis, and biochemical blood analysis may indicate hidden glomerular injury. Focusing on the markers of renal damage in the preoperative period allows for determining the indications for intraoperative nephrobiopsy during surgical treatment of renal cysts. This facilitates early morphological identification of glomerulopathy and timely initiation of nephroprotective therapy to reduce the risk of chronic kidney disease progression.