From the Guidelines
Multiple simple renal cysts in the kidneys are generally benign and do not typically require treatment if they are asymptomatic and have typical features on imaging. The presence of multiple simple renal cysts is a common finding, especially in individuals over the age of 50, and is often discovered incidentally during imaging for other conditions 1. According to the KDIGO 2025 clinical practice guideline, the focus is on autosomal dominant polycystic kidney disease (ADPKD), which is a distinct entity characterized by multiple, bilateral kidney cysts causing progressive kidney enlargement, commonly associated with hypertension and liver cysts 1.
In contrast, simple renal cysts are typically not associated with these complications and do not require specific medication or intervention. However, it is essential to distinguish simple cysts from complex cysts or polycystic kidney disease, which have different implications. Simple cysts develop when tubules in the kidneys become blocked and fill with fluid, and while generally harmless, any new symptoms like flank pain, blood in urine, or frequent urinary tract infections should be reported to a doctor, as these might indicate complications requiring attention.
Key points to consider:
- Multiple simple renal cysts are common and usually benign
- Asymptomatic cysts with typical features on imaging typically require no treatment
- Follow-up imaging may be recommended to ensure the cysts remain stable
- It is crucial to distinguish simple cysts from complex cysts or polycystic kidney disease
- New symptoms such as flank pain, blood in urine, or frequent urinary tract infections should be reported to a doctor.
From the Research
Implications of Multiple Simple Renal Cysts
- The presence of multiple simple renal cysts has been associated with hypertension, particularly in males, persons over the age of 60 years, and those with a glomerular filtration rate (GFR) greater than 60 ml/min/1.73 m2 2, 3.
- The number and size of cysts are independent risk factors for the prevalence of hypertension, with larger cysts and multiple cysts having a greater impact on blood pressure 2, 3.
- Simple renal cysts are also associated with blood cell count disturbances, including increased hematocrit, hemoglobin, and red blood cells 4.
- Treatment of simple renal cysts, such as aspiration of cyst fluid with injection of sclerosing agent or laparoscopic/retroperitoneoscopic decortications of the cyst wall, can decrease blood pressure in patients with hypertension and relieve loin pain in a significant proportion of patients 4.
- The presence of multiple renal cysts, particularly those located on both kidneys, may be associated with a higher incidence of hypertension 3.
- Recent studies have also suggested that kidney cysts, particularly those in the medulla, may be associated with progressive chronic kidney disease (CKD) and could serve as a useful imaging biomarker for CKD risk 5.
Clinical Significance
- The clinical significance of simple renal cysts is still a topic of debate, with some studies suggesting that they may be associated with malignant change or the development of hypertension 6.
- However, the majority of simple renal cysts are considered benign and do not require treatment unless they are causing symptoms or complications 4, 2, 3.
- The presence of a simple renal cyst should not preclude kidney donation, but occult renal disease should be excluded and appropriate donor assessment performed 6.