Management of Renal Cortical Cysts

Simple Cysts in Adults

The American College of Radiology recommends that asymptomatic simple cysts (Bosniak class I and II) require no further evaluation or follow-up, as they are extremely common and do not require routine surveillance, affecting approximately 50% of individuals older than 50 years, with no routine surveillance needed for uncomplicated simple cysts 1

Complex cysts with septations, calcifications, internal echoes, or irregularities need further characterization, as they may require excision due to malignancy risk 1

The American Academy of Pediatrics and the National Institute of Diabetes and Digestive and Kidney Diseases suggest that detection of a solitary cyst in childhood requires follow-up imaging, as simple cysts are rare in children, and a solitary cyst is very likely a sign of ADPKD, though rarely the cyst may not be confirmed on follow-up 2, 3, 4
Multiple kidney cysts in childhood are highly suggestive of ADPKD or another cystic nephropathy and require clinical work-up 2, 3, 4

The American College of Radiology recommends that ultrasound is first-line for characterizing simple cysts, and CT or MRI is required to distinguish hemorrhagic cysts from malignant tumors when complexity is detected 1
MRI with contrast may upgrade cyst complexity compared to CT, potentially altering management 5

The American College of Radiology suggests that in patients with history of kidney disease, hypertension, or diabetes, routine ultrasound surveillance of simple cysts has minimal impact on diagnosis and management, but ultrasound may be indicated when there is prior history of stones or obstruction, frequent urinary tract infections, or family history of autosomal dominant polycystic kidney disease 6