Differentiation of Bosniak categories IIF and III cystic masses: what radiologists should know.

Based on a review of the literature, we describe old and new features that both old and new radiologists should be aware of (a) to determine which imaging features affect the differentiation of categories IIF and III masses, (b) to show imaging features of benign cystic renal masses preoperatively diagnosed as category III, and (c) to introduce imaging techniques that help to differentiate categories IIF and III masses without requiring the use of CT or magnetic resonance contrast material.