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Bosniak grading system

Indications: - Bosniak grading system is used with CT scanning to characterize renal cysts Interpretation: - Septa, enhancing nodules, & calcifications are considered in the grading system - Bosniak 1 lesion: a completely fluid simple renal cyst - Bosniak 2 lesion: - a renal cyst with thin hairline septa that do not enhance or thin calcifications in the septa or wall - risk of malignancy is ~0% [1] - Bosniak 2F lesion: - cystic lesions with multiple thin septa, septa thicker than hairline, a slightly thick cyst wall, or calcification, which may be thick - intrarenal, nonenhancing, high-attenuation cysts >= 3 cm - examples of moderately complex renal cysts Bosniak category IIF in refs [1,2] - cannot be fully characterized as benign - 5-25% of lesions malignant [1] - Bosniak 3 lesion: - renal cyst with uniform wall thickening or mural nodule, thick or irregular calcification, & thick enhancing septa - ~50% are malignant - complex renal abscess due pyelonephritis may masquarade as a Bosniak 3 complex renal cyst [1] - Boniak 4 lesion: - all the characteristics of Bosniak 3 lesions plus enhancing soft-tissue components adjacent to, but independent of, the wall or septa - >90% risk of malignancy [1]

General

numerical rating scale (NRS)

References

  1. Thomas S, Grimm L, Brady MP Renal Cell Carcinoma: Recognition and Follow-up. Medscape. April 18, 2016 http://reference.medscape.com/features/slideshow/renal-cell-carcinoma
  2. Israel GM & Bosniak MA Follow-up CT of moderately complex cystic lesions of the kidney (Bosniak category IIF). AJR AM J Roentgenol 181:627, 2003 PMID: 12933451