What are renal cysts?
Fluid filled sacs found in the kidney
They can either be classified as simple or complex
Explain simple cysts
Well-defined outline and homogenous features.
Common in older patients with prevalence of up to 50% in those over 50.
They are thought to develop from the renal tubule epithelium in response to previous ischaemia.
Explain complex cysts
Calcifications or hetergenous enhancements on imaging.
All complex cysts have risk of malignancy that increases in proportion with complexity
Genetic conditions like Polycystic kidney disease, tuberous slcerosis and von Hippel-Lindau disease
What is ADPKD?
Inherited condition (autosomal recessive) by mutations in PKD1 or PKD2 leading to multiple renal cysts formation.
It can also cause berry aneurysms in brain leading to SAH.
Mitral valve disease and liver cysts are also associated with ADPKD.
They will eventually develop end-stage renal failure and may require dialysis or renal transplant.
Clinical features or renal cysts
Usually found incidentally on abdo imaging.
They are usually asymptomatic, especially if siple.
Flank pain if the cyst ruptures or haematuria.
Patients with polycystic kidney disease can also present with uncontrolled HTN and flank mass.
Renal cell carcinoma
CT or MRI imaging with pre- and post- enhancement scans with IV contrast
USS often picks up incidental findings, but will still require further imaging with CT or MRI.
Bloods especially U&Es to see renal function.
You want to check serum glucose, blood pressure, possibly urine dipstick and urinalsysis as well etc...
What classification system is used for cysts?
Bosniak scoring system
Explain Bosniak Scoring system
Uses contrast-enhanced CT scan data to classify into five stages.
Risk of malignancy increases with increasing stage
Explain the five stages of Bosniak Scoring System
Management of asymptomatic simple cysts
No need for further follow-up or treatment.
Management of symptomatic simple renal cysts.
Needle aspiration or cyst deroofing may be warranted if it is significantly impacting the patient.
Management of complex cysts
II -> No follow up needed
II F -> CT scan at 3, 6 and 12 months (continued surveillance)
III -> Surveillance or surgical considering nephrectomy
IV -> Surgical considering nephrectomy
Usually rare but include infection, haemorrhage and rupture.
Depends on complexity and their risk of malignancy