Treatment of Simple Renal Cysts
For asymptomatic simple renal cysts (Bosniak I and II), no treatment or follow-up imaging is required. 1, 2, 3
Management Algorithm
Asymptomatic Simple Cysts
- No intervention is necessary for simple renal cysts that meet all diagnostic criteria: well-defined margins, absence of internal echoes on ultrasound, no contrast enhancement on CT or MRI, and thin posterior walls 1, 2
- No routine surveillance imaging is needed regardless of cyst size, as these lesions carry approximately 0% malignancy risk 1, 3
- Treatment success for any intervention is defined by symptom relief rather than volume reduction 2
Symptomatic Simple Cysts
If a simple cyst becomes symptomatic (causing pain, infection, or other complications):
- Laparoscopic cyst decortication may be considered for symptomatic cysts that fail aspiration and sclerotherapy 3
- For infected simple cysts with lumbar accessibility, percutaneous puncture with synchronous sclerosis plus parenteral antibiotic therapy (such as ciprofloxacin) is the recommended treatment 4
Critical Monitoring Considerations
When to Escalate Care
Any change in cyst characteristics warrants immediate further investigation with contrast-enhanced CT or MRI due to increased malignancy risk 2, 3:
- Development of internal septations
- Wall thickening
- Solid components
- Calcifications
- Irregular enhancement
These changes may indicate progression to a higher Bosniak category requiring different management strategies 2
Important Pitfalls to Avoid
- Surgery for Bosniak II cysts constitutes overtreatment and should be avoided 1
- Never assume a nondiagnostic biopsy indicates benignity if tissue sampling is performed 2
- Core biopsies are not recommended for cystic renal masses due to low diagnostic yield unless solid components are present 2, 3
- In children with a solitary cyst and positive family history, follow-up imaging is required as this may represent early autosomal dominant polycystic kidney disease 2
Special Population Considerations
- Simple renal cysts may be associated with hypertension, particularly when multiple cysts are present, though this does not change the non-interventional approach for asymptomatic lesions 2
- The presence of a Stage I (Bosniak I) renal cyst should not preclude kidney donation, though appropriate donor assessment should be performed 5