Guidelines on the management of renal cyst disease

There are no randomized controlled trials with regards to follow-up or management of cystic renal masses, as such, the recommendations are primarily expert opinion. At this time, category I and II renal cysts, do not require further imaging or follow-up. Patients in Category IIF, because of the approximate 5% malignant risk, do require periodic imaging. (There is no consensus or evidence based interval determined for follow-up imaging.) Combination of ultrasound and MRI should be considered as follow-up for Bosniak IIF and reduces the lifetime radiation dose (once the lesion has been characterized by triphasic CT scan) in patients younger than 50 years. For Category III (50% malignant risk) and category IV (75% to 90% malignant risk), surgical excision is recommended.9–13 (Level 3 evidence, Grade B recommendation). Although MRI may add further information, it should be used as an adjunct to CT scans in difficult cases (Level 4 evidence, Grade C recommendation).