INTERDISCIPLINARY DISCUSSIONS IN LOCALISED RCC DIAGNOSIS AND SURGICAL STRATEGIES FOR ATYPICAL RENAL CYSTIC LESIONS. Maria Cova

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1 INTERDISCIPLINARY DISCUSSIONS IN LOCALISED RCC DIAGNOSIS AND SURGICAL STRATEGIES FOR ATYPICAL RENAL CYSTIC LESIONS Maria Cova Radiology Department University of Trieste (IT) Eleventh European International Kidney Cancer Symposium April 2016, Barcelona, Spain

2 SIMPLE RENAL CYST Commonest focal renal lesion More often identified incidentally at US Incidence varies with age, sex, renal function and other factors

3 SIMPLE RENAL CYST Fully characterized on US, no further imaging necessary - Thin wall - Anechoic content - Back enhancement - (Lateral acoustic shadows)

4 SIMPLE RENAL CYST Fully characterized also on CT - Thin wall, no calcifications - Water content - Sharp interface with adjacent renal parenchyma - No enhancement

5 SIMPLE RENAL CYST Fully characterized also on CT and on MR T2 T1 T1 + Gd Subtraction

6 COMPLEX RENAL CYST Full characterization often impossible on grey-scale US only Other imaging modalities are required (CT/MR/CEUS) - Septa and calcifications - Echogenic content (hemorrhage, debris) - Inflammatory changes

7 QUESTIONS Is it a cyst? Is it a benign or malignant cyst?

8 QUESTION 1 Is it a cyst? Unenhanced CT scan 20 HU or less: benign renal cyst HU: indeterminate Homogeneous renal mass >70 HU: >99.9% chance of representing a high attenuation benign renal cyst Jonisch AI, Radiology 2007 O Connor SD, AJR 2011

9 QUESTION 1 Is it a cyst? Lesions not characterized on CT single phase Unenhanced CT scan

10 QUESTION 1 Is it a cyst? Equivocal enhancement on CT 30 HU 36 HU 45 HU In our opinion, a renal mass that enhances HU is indeterminate and needs further evaluation for definitive characterization Israel GM, Radiology 2005

11 QUESTION 1 Is it a cyst? 49 HU 65 HU

12 QUESTION 2 Is it benign or malignant cyst? Bosniak classification First introduced by Bosniak in 1986 for CT Applied also to MRI and CEUS Widely used to differentiate surgical from non-surgical complex cystic lesions Five categories, increasing risk of malignancy

13 Bosniak classification - CT Category II Minimally complicated benign cysts Few septa, perceivable enhancement Thin calcifications Homogeneous attenuation (<3cm)

14 Bosniak classification - CT Category IIF Probably benign cysts that have some suspicious feature and need follow-up to detect any change in character 16 months after

15 Bosniak classification - CT Category III Indeterminate cystic masses Uniform wall thickening, or wall and septal irregularities Enhancing wall and septa

16 Bosniak classification - CT Category IV I likely malignant cystic masses Non-uniform enhancing thick wall and septations Enhancing nodules and solid components

17 Bosniak classification - CT Remember The Bosniak classification is clinically oriented, and clinic is important! Follow-up Follow-up Category III Category III

18 Bosniak classification - MRI Successfully used also for MRI CT vs. MRI (69 complex cysts) 56 lesions (81%): Similar findings 8 lesions (12%) more septa at MRI 7 lesions (10%) increased wall and/or septa thickness at MRI 2 lesions (3%) different enhancement MRI does not identify calcifications Upgrade at MRI in 7 lesions II>IIF (n=2) IIF>III (n=3) IIF>IV (n=2) Israel GM, Radiology 2004

19 Bosniak classification - CEUS CEUS is at least as effective as CT in the characterization of complex renal cysts Reference procedure: helical CT Ascenti, Radiology 2007 Park, Eur J Radiol 2007 Quaia, AJR 2008 Clevert, Clin Hemorheol Microcirc 2008

20 Bosniak classification - CEUS Advantages Very high sensitivity to flow (hypovascular lesions) No need for nephrotoxic contrast agents No radiation no need to limit the number of examinations

21 Bosniak classification - CEUS Limitations Calcifications (can mask cystic content) Very large cysts (insufficient panoramicity) Staging of cystic tumours impossible

22 Bosniak classification Which imaging? CT: widest experience (since 1986) - Radiation, nephrotoxic contrast agents MRI: limited experience (only few investigations) - Cannot be performed in all patients CEUS: More robust than MRI (more investigations)

23 Bosniak classification Which imaging? Comparative studies: results are equivalent, but not equal on a per-patient basis. Differences exist Bosniak MA, Radiology 1986 Bosniak MA,Urol Radiol 1991 Israel GM, AJR 2003 Israel GM, Radiology 2004 Ascenti G, Radiology 2007 Park BK, Eur J Rad 2007 Quaia E, AJR 2008

24 IIF III III

25 IIF III III II IIF IIF

26 IIF III III II IIF IIF IV IV IV

27 Bosniak classification Which imaging? CEUS preferable (inexpensive, no radiation, no nephrotoxic contrast agents) MR in heavily calcified lesions CT for staging (more panoramic) More than one technique in difficult cases

28 THANK YOU FOR YOUR ATTENTION