An update of the Bosniak renal cyst classification system

Abstract

w m s [ i s m t n he Bosniak renal cyst classification was first introduced in 19861 and has been accepted by rologists and radiologists as a way of diagnosing, iscussing, and determining the management aproach to cystic renal masses.2–4 Using the lesion’s orphology and enhancement characteristics, ach lesion can be categorized into one of five roups (categories I, II, IIF, III, and IV; Table I), ith associated recommendations for patient treatent. With additional experience during the past wo decades, the Bosniak renal cyst classification as been updated and refined.5,6 However, pubished reports have incorrectly described and aplied the classification system,7–10 leading to conusion in its use that could be detrimental to atient care. Therefore, the purpose of this comentary is to present an up-to-date version of the osniak renal cyst classification, point out potenial errors in its use, and present our approach to he evaluation of cystic lesions of the kidney. We elieve that this is particularly relevant in this age f laparoscopic surgery and ablative techniques. ecause these procedures are less invasive, there ay be a tendency to treat patients using these techiques on the basis of imaging studies that are not echnically adequate or have been interpreted incorectly. High-quality imaging studies are needed for ccurate characterization of renal masses to avoid unecessary surgery, even if it is minimally invasive. One of the major changes in the original classifiation was the introduction of category IIF (F for ollow-up), which was added to include cystic leions that are slightly more complex than category I, but not complex enough to fulfill the criteria for ategory III.6,11–13 This category was introduced on he basis of experience gained after the removal of enign category III cysts. Category IIF lesions are