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1、肾脏囊性占位,Introduction,Ignore,Follow or ExciseRadiological InterpretationCalcificationHyperdense or High signalSeptationsEnhancementMultiloculatedNodularityWall thickeningRole of BiopsyDr Bosniaks opinionBosniak Classification of Renal Cystic Disease,Renal cysts are commonly encountered lesions in dail
2、y radiological practice.Usually these are simple benign cysts,but they can become complicated in case of hemorrhage,infection and ischemia.When this occurs it can be difficult to differentiate these complicated cysts from cystic renal cell carcinomas(10%of all renal cell carcinomas)Since the only tr
3、eatment for renal cell carcinoma is surgery or ablation,we need to recognize these cystic renal cell carcinomas.Imaging is a reliable means for differentiating benign from malignant cystic lesions.,Even on gross examination a cystic renal cell carcinoma(left)may be indistinguishable from a complicat
4、ed cyst(right),Ignore,Follow or ExciseRenal cysts can be classified according to the Bosniak classification depending on their features.Type Icysts are simple cysts.Type IIare the minimally complicated cysts.Type I and II can be ignored.Type II Fare probably benign,but need to be followed.Type III a
5、nd IVboth are surgical lesions.Type IV is inevitably malignant and in the type III group about 80-90%turn out to be malignant as well.In our communication with the clinicians it is important,that we explain the significance of our findings and the meaning of the classification in terms of:Ignore(typ
6、e I and II),Follow(type IIF)or Excise(type III and IV).So in this lecture we will only talk about Ignore,Follow or Excise.For those who want to see the original Bosniak classification,look at the table which is presented at the end of the lecture.,Radiological InterpretationAlthough the final differ
7、entiation of cystic renal masses is based upon histologic diagnosis,there are imaging findings that tell you that a cyst is not a simple cyst and whether it is probably benign or malignant.The following imaging features indicate that a cyst is NOT simple:-Calcification-Hyperdense/high signal-Septati
8、ons-Multiple locules-Enhancement-Nodularity/wall thickening,Differentiation is based upon histologic diagnosis,but Imaging is a reliable means for differentiating benign from malignant cystic lesions,The table on the left summarises these imaging features together with the management consequences:Ig
9、nore,Follow or Excise.When we look at these imaging features,we have to realise,that the most worrisome portion of a cystic mass should be used in deciding appropriate management.So when the findings are discordant either within one examination or using different radiological examinations,the lesion
10、 should be managed based upon the most aggressive imaging findings.When we look at the table on the left,we can say that we are pretty good with the first 3 parameters(calcification,hyperdens and septations),because we are correct in about 95%of the cases.The other four are even more easy,because wh
11、en you have any of these(enhancement,multiloculated,nodularity or wall thickening),the lesion is almost always a surgical lesion.Regarding follow up,there are no rules at the moment.One could do a follow up at 6 months and if the lesion is stable then double the follow up time.We will now discuss al
12、l these imaging features in detail.,Calcification,The most important thing is a good description of the type of calcifications.We can ignore small amounts of calcification that are smooth,septal or if it is milk of calcium,which moves to the lowest point with positional changes.We have to make sure,
13、that no enhancement(=All lesions that show enhancement and lesions with wall thickening or nodularity of the wall outside the calcifications should be excised.We can follow lesions with thick or nodular calcification without any enhancement.,Benign calcifications:small punctate and milk of calcium.I
14、gnore,On the left we see a cystic lesion.There is a small punctate calcification that we can ignore.On the bottom of the cyst there is a layer of calcium typical for milk of calcium.This is also a benign calcification that we can ignore.,LEFT:NECT with a smooth linear calcification and nodular calci
15、fication.RIGHT:Enhanced CT shows enhancement.Excise,On the left a patient with nefrolithiasis.There is also a cystic lesion with linear and nodular calcification.If there were only these linear calcifications we could ignore the lesion.In case of nodular calcification we can follow it,if there is no
16、 enhancement.In this case however we see enhancement,so this lesion has to be excised.,On CT hyperdense means:20 HU on a NECTOn MRI hyperintense means all that has higher signal intensity than water on a T1 weighted image.Hyperdensity or hyperintensity usually indicates hemorrhage or high protein co
17、ntent of the cyst.Ignoreall lesion with sharp margins;lesions On US they have to be clearly cysticFollowall lesions that are totally intrarenal,because you can not appreciate the wall and follow all lesions 3 cm,because there is at the moment not much experience with these lesions.All these lesions
18、must show no enhancement.Exciseall lesions that are poorly defined or heterogenous or show enhancement.Also when ultrasound shows that the lesion is solid,the lesion should be excised.,Hyperdense or High signal,LEFT:NECT shows a lesion with a density of 27 HU.IgnoreRIGHT:MRI shows a intrarenal lesio
19、n that is hyperintense on T1:higher signal than water.Follow,On the left we see a hyperdens cystic lesion on CT and a hyperintense lesion on a T1-weighted MR.Both lesions have a sharp margin and are homogeneous,although there is some noise in the CT image.On the enhanced scans(not shown)the lesions
20、didnt show any enhancement.We therefore can ignore the lesion on the left and we have to follow the lesion on the right,because it is totally intrarenal.,Septations,Ignorethin septations(Followall septations that are only slightly greater than hairline.They still have to show no enhancement.Exciseal
21、l septations that are thick,irregular or nodular and all septations that show enhancement.,LEFT:thin,smooth septation.IgnoreRIGHT:thick enhancing septation.Excise,On the left we see 2 casesThere is a cystic lesion with a thin smooth non enhancing septation that we can ignore.The other case is a thic
22、k enhancing septation that has to be excised.,Cystic lesion with thick septation and a nodule.Excise,The ultrasound image on the left shows a thick septation.There is also a nodule in the wall of the cyst.So we have two reasons to excise this cystic lesion.,Enhancement,Enhancement is our best predic
23、table sign of malignancy.So we have to excise all lesions,that clearly show enhancement.The only exception is infection.,Significant enhancement:Unenhanced CT:44 HU(left)Enhanced scan:61 HU(right).Excise,Enhancement is defined as follows:Increase in Hounsfield Units of the mass after contrast inject
24、ion:10-15 HU=indeterminate15 HU=vascularityOn MR:15%=enhancement=surgical,Enhanced CT shows enhancement of a thick wall and a central area.excise,The case on the left doesnt shows much on the NECT.However when we give contrast we can appreciate a thick wall and we see enhancement both of the wall an
25、d of a central area in the medial part of the cystic lesion.We should never see this in an benign cyst,so this is a surgical lesion.,Multiloculated,Masses with three or more septa are not called multiseptated but multiloculated.All multiloculated lesions should be excised,unless there is clear evide
26、nce of infection.,Multiloculated cystic mass on US and on CT.Excise,In the adult,the two most common multiloculated masses are MLCN(multilocular cystic nephroma)which is usually benign,but sometimes malignant and MLRCC(multilocular renal cell carcinoma)which is always malignant.On imaging there is n
27、o way that we can separate these two and therefore,all multiloculated masses are surgical(unless infection).,Multilocular renal cell carcinoma(left)and a multilocular cystic nephroma(right),Even the pathologist can not separate the usually benign multilocular cystic nephroma from the malignant multi
28、locular renal cell carcinoma on gross specimen.The differentiation is based on the histology of the epithelial cells lining these locules.So all multilocular renal masses have to be excised.,Nodularity,Ignore:noneFollow:only very small nonenhancing nodules,and follow carefullyExcise:all other nodula
29、r lesions,Very small non enhancing nodules.Follow,The case on the left shows very small nodules on a CECT and a T2WI.From all the other images we could tell that they were not enhancing.So we can probably follow this lesion.If they start to grow or show any enhancement,then we have to excise the les
30、ion.,Cystic lesion with a big enhancing nodule.Excise,On the left an easy case.There is a big nodule with enhancement,so this lesion has to be excised.Even if there was no enhancement,the lesion still had to be excised.,T2WI shows a multiloculated cystic mass with multiple nodules.Excise,The case on
31、 the left is a T2WI with Fatsat.We see multiple nodules so this mass has to be excised.It doesnt matter whether or not these nodules enhance.,Wall thickening,All lesions with a thickened wall,with or without enhancement,should be excised,unless there is clear evidence of infection.In these latter ca
32、ses the lesions should be followed.,Two cysic lesions with a regular thick wall.Excise,On the left we see two renal lesions that are cystic.The lesion on the far left clearly shows a thickened wall.This is easy to appreciate because part of the lesion is extrarenal.The cystic lesion next to it is to
33、tally intrarenal,which makes it harder to appreciate,but there is wall tickening.So both lesions have to be excised,whether there is enhancement of the wall or not.The only exception would be if there were evident signs of infection.,Cystic lesion with a thick irregular enhancing wall.Excise,The cys
34、tic lesion on the left is clearly a surgical lesion.It has a thick irregular wall,it is exophytic and shows enhancement.,Role of Biopsy,In the literature there are different opinions concerning the role of biopsy in renal cystic lesions.Here we provide Dr Bosniaks opinion.A different opinion is give
35、n by Dr Lang in the artice on CT-guided biopsy of indeterminate renal cystic masses(Bosniak 3 and 2F):accuracy and impact on clinical management(see references),Dr Bosniaks opinionBiopsy plays a limited role.Only in case of clinical suspicion that the mass is inflammatory(pyuria,etc.)or there is rad
36、iological evidence suggesting inflammation(such as perinephric fat stranding),puncture is acceptable.When the outcome is infection,the lesion can be treated and followed.Although considered rare,needle track spread of tumor is an underestimated risk.A core biopsy of the wall of a cystic lesion(benig
37、n or malignant)can cause it to rupture and spill its contents into the surrounding tissues.A negative biopsy result does not rule out malignancy,particularly in cystic lesions that have less bulk of tissue to sample.,Bosniak Classification of Renal Cystic Disease,The Bosniak classification was descr
38、ibed in 1986.After the original description,it became obvious that some revision was needed because there were some category II cysts that were slightly more complicated than most category II lesions,but not complicated enough to place them in category III.For that reason,a category IIF(F for follow
39、-up)was introduced in 1993.Category I(simple cysts),Category II(mildly complicated benign cysts),andCategory IV(cystic neoplasms)are easy to diagnose.Their clinical management is straightforward,with surgery indicated for category IV masses while category I and II masses can be dismissed as benign.C
40、ategory IIF(F for follow-up;moderately complicated cystic masses that require follow-up imaging to demonstrate stability and therefore benignity)andCategory IIImasses(indeterminate masses that require surgery in most cases)can be difficult to differentiate and are subject to interobserver variability.This distinction is essential because their treatment is different.,
