Mar 5, 2026 · The proposed new version of Bosniak classification of cystic renal masses is the first major revision since the death of the American radiologist Morton Bosniak (1929-2016), who died …

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The Bosniak classification predicts likelihood of cancer, not biologic behavior, and it can not differentiate indolent lesions from aggressive ones. The Bosniak classification is based on the anatomic futures of …

Features on CT images are compatible with Bosniak class III left renal cystic mass, according to Bosniak classification version 2019 up to 50% of Bosniak class III lesions are malignant.

In addition, an 8 mm enhancing mural node is observed at the posteromedial aspect (Bosniak class IV). Additionally, several subcentimeter simple cortical cysts in both kidneys.

Case Discussion Left renal cystic lesion (Bosniak class IV) - pathologically proven renal cell carcinoma.

Right lower pole renal cyst with a single thin septation. Both cysts fall into the 'minimally complex' Bosniak II category and can be confidently said to be benign without follow-up imaging required. …

Case Discussion Most Bosniak class IV masses are malignant and need surgical resection.

Citation: Niknejad, M. Cystic renal mass Bosniak classification version 2019 - pearls and pitfalls, Radiopaedia 2023 Virtual Conference (26 Jul 2023) https://doi.org/10.53347/rPoster-1669

Diagram of a Bosniak 2F lesion. Original case courtesy of Dr Matt Skalski, rid 20989.