LAUSR

Abstract Objectives: To analyse the management, pathology and outcomes of complex renal cystic masses (CRCM) and to develop a decision-making tool for daily clinical care using the Bosniak classification system for CRCM. Patients and methods: A comprehensive dataset of 185 patients with 188 CRCM and a minimum follow-up of 3 years were analysed for management, pathology and outcomes. Results: We analysed 35 Bosniak II, 34 Bosniak IIF, 58 Bosniak III, and 61 Bosniak IV lesions. The overall incidence of renal cell carcinoma was 8.6%, 29.4%, 62.1%, and 78.7% for each category. Based on our surveillance strategy of Bosniak IIF masses, we recommend computed tomography (CT)/magnetic resonance imaging (MRI) every 2 years after the initial examination. We also recommend performing one MRI (as an adjunct to CT) during the early follow-up period (<4 years). The use of MRI correlation for differential diagnostic purposes has proven useful for marginal Bosniak II, IIF and III cases. Conclusions: From our data, we have created a decision-making protocol to guide urologists in planning a safe and effective diagnostic and treatment strategy for CRCM. The Bosniak classification is a useful tool for clinical decision-making. Uncertainties still remain for Bosniak IIF and III lesions. Our protocol shows that individualised decision-making is necessary in a significant proportion of CRCM.