Evolution of Bosniak IIF Renal Cysts and Impact of the 2019 Bosniak Classification

Upgrading and malignancy rates among Bosniak IIF cysts was markedly lower than traditionally reported. No patient had a significant progression beyond 36 months. More than 20% of Bosniak IIF cysts were initially overdiagnosed. The 2019 Bosniak classification may help to reduce the overdiagnosis of Bosniak IIF lesions requiring follow-up.