CUA: Cystic Renal Lesions (2017): Difference between revisions

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'''See [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5365391/ Original Guideline]'''

'''*****All information below contained in more inclusive Benign Renal Tumours Chapter Notes'''

'''*****All information below contained in more inclusive [[Benign Kidney Tumours|Benign Renal Tumours]] Chapter Notes'''

~~===~~== Bosniak Renal Cyst Classification ~~===~~==

== Bosniak Renal Cyst Classification ==

* '''If a complex cyst is first identified on US, contrast-enhanced axial imaging should be performed to better characterize the cyst'''

* '''If a complex cyst is first identified on US, contrast-enhanced axial imaging should be performed to better characterize the cyst'''

* '''See Table 1 from Original Guideline'''

* '''See [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5365391/table/t1-cuaj-3-4-e66/ Table 1 from Original Guideline]'''

* '''Risk of malignancy'''

* '''Risk of malignancy'''

** '''Bosniak II: 5%,''' likely gross overestimation of the true risk, as most of the malignant category II lesions had features that made them too complex to be considered a true category II cyst

** '''Bosniak II: 5%,''' likely gross overestimation of the true risk, as most of the malignant category II lesions had features that made them too complex to be considered a true category II cyst

** '''Bosniak IIF: 8-27%'''

** '''Bosniak IIF: 8-27%'''

** '''Bosniak III: 54%'''

** '''Bosniak III: 54%'''

** '''Bosniak IV: 88%, malignant until proven otherwise'''

** '''Bosniak IV: 88%, malignant until proven otherwise'''

==~~=== '''~~Intervention and follow-up~~''' ===~~==

== Intervention and follow-up ==

* '''Bosniak I~~'''~~

=== Bosniak I ===

** '''Follow-up for Bosniak I cysts is not warranted'''

* '''Follow-up for Bosniak I cysts is not warranted'''

*** Majority will grow over time; growth should not necessarily be considered a sign a malignancy

** Majority will grow over time; growth should not necessarily be considered a sign a malignancy

*** Transformation into a more complex cyst is rare and has been reported in only a handful of cases

** Transformation into a more complex cyst is rare and has been reported in only a handful of cases

** '''Intervention is only warranted if the cyst becomes symptomatic''' (i.e., bleeding, recurrent infection or pain)

* '''Intervention is only warranted if the cyst becomes symptomatic''' (i.e., bleeding, recurrent infection or pain)

*** Treatment options include: percutaneous management (aspiration +/- sclerotherapy) or surgery

** Treatment options include: percutaneous management (aspiration +/- sclerotherapy) or surgery

*** Percutaneous cyst decompression may also be considered prior to offering definitive treatment as a means to confirm that the source of symptoms are cyst-related.

** Percutaneous cyst decompression may also be considered prior to offering definitive treatment as a means to confirm that the source of symptoms are cyst-related.

* '''Bosniak II'''

** '''Follow-up for Bosniak II cysts is not warranted'''

** '''Intervention is only warranted if the cyst becomes symptomatic'''

* '''Bosniak IIF'''

** '''≈15% of these category IIF cysts will progress in complexity (to Bosniak category III or IV)''' over time

** '''Should be followed with a contrast-enhanced CT scan or MRI every 6 months for the first year. Cases without progression should be followed annually for at least 5 years.'''

* '''Bosniak III'''

** '''Surgical excision is generally suggested'''

*** '''Given the low metastatic potential of cystic RCC, the panel feels that reduced surgical margins and controlled cyst decompression (if required) can be performed with low risk of tumour recurrence.'''

*** '''Likewise, due to the same reason, active surveillance and thermal-ablation therapies may also be considered as appropriate treatment alternatives in select cases'''

* '''Bosniak IV'''

** '''Surgical excision is generally suggested'''

*** '''Most of these malignant cysts are thought to have low metastatic potential and thus, more conservative management may be safely considered in select cases'''

===== '''~~Role~~ of ~~active surveillance~~ for ~~suspected~~ cystic RCC''' =====

=== Bosniak II ===

* '''Follow-up for Bosniak II cysts is not warranted'''

* '''Intervention is only warranted if the cyst becomes symptomatic'''

=== Bosniak IIF ===

* '''≈15% of these category IIF cysts will progress in complexity (to Bosniak category III or IV)''' over time

* '''Should be followed with a contrast-enhanced CT scan or MRI every 6 months for the first year. Cases without progression should be followed annually for at least 5 years.'''

=== Bosniak III ===

* '''Surgical excision is generally suggested'''

** '''Given the low metastatic potential of cystic RCC, the panel feels that reduced surgical margins and controlled cyst decompression (if required) can be performed with low risk of tumour recurrence.'''

** '''Likewise, due to the same reason, active surveillance and thermal-ablation therapies may also be considered as appropriate treatment alternatives in select cases'''

=== Bosniak IV ===

* '''Surgical excision is generally suggested'''

** '''Most of these malignant cysts are thought to have low metastatic potential and thus, more conservative management may be safely considered in select cases'''

== Role of active surveillance for suspected cystic RCC ==

* '''The vast majority of cystic RCCs are multilocular cystic RCCs (mcRCC,)''' but all RCC subtypes may present in a predominantly cystic form. '''Cystic RCCs need to be distinguished from solid renal masses with necrotic components, which behave more aggressively.'''

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*# '''Fast-growing nodule'''

==~~=== '''~~Thermal-ablation therapies~~''' ===~~==

== Thermal-ablation therapies ==

* '''Given the limited data, RFA should be limited to patients with small Bosniak category III and IV cysts who are poor operative candidates and in whom active surveillance is not being considered'''

* '''The role of cryotherapy in the management of Bosniak III or IV cysts is not well-defined,''' with only a handful of cases reported to have been treated by the approach in the literature.

==~~=== '''~~Role of renal tumour biopsy in the management of cystic lesions~~''' ===~~==

== Role of renal tumour biopsy in the management of cystic lesions ==

* There is evidence that RTBs are significantly less informative for the diagnosis of cystic lesions than for solid ones.

* '''It is generally felt that RTB is not diagnostic for most Bosniak III cysts, as there is minimal targetable solid component.'''

* '''For Bosniak IV cysts, a biopsy of the solid component may be considered to confirm the presence of a malignant tumour and to help with decision-making in select cases (elderly, multiple comorbidities, unfit for treatment, etc).'''

@@ Line 1: / Line 1: @@
 '''See [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5365391/ Original Guideline]'''
-'''*****All information below contained in more inclusive Benign Renal Tumours Chapter Notes'''
+'''*****All information below contained in more inclusive [[Benign Kidney Tumours|Benign Renal Tumours]] Chapter Notes'''
-===== Bosniak Renal Cyst Classification =====
+== Bosniak Renal Cyst Classification ==
-* '''If a complex cyst is first identified on US, contrast-enhanced axial imaging should be performed to better characterize the cyst'''
+* '''<span style="color:#ff0000">If a complex cyst is first identified on US, contrast-enhanced axial imaging should be performed to better characterize the cyst</span>'''
-* '''See Table 1 from Original Guideline'''
+* '''<span style="color:#ff0000">See </span>[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5365391/table/t1-cuaj-3-4-e66/ Table 1 from Original Guideline]'''
-* '''Risk of malignancy'''
+* '''<span style="color:#ff0000">Risk of malignancy</span>'''
-** '''Bosniak II: 5%,''' likely gross overestimation of the true risk, as most of the malignant category II lesions had features that made them too complex to be considered a true category II cyst
+** '''<span style="color:#ff0000">Bosniak II: 5%</span>,''' likely gross overestimation of the true risk, as most of the malignant category II lesions had features that made them too complex to be considered a true category II cyst
-** '''Bosniak IIF: 8-27%'''
+** '''<span style="color:#ff0000">Bosniak IIF: 8-27%</span>'''
-** '''Bosniak III: 54%'''
+** '''<span style="color:#ff0000">Bosniak III: 54%</span>'''
-** '''Bosniak IV: 88%, malignant until proven otherwise'''
+** '''<span style="color:#ff0000">Bosniak IV: 88%</span>, malignant until proven otherwise'''
-===== '''Intervention and follow-up''' =====
+== Intervention and follow-up ==
-* '''Bosniak I'''
+=== Bosniak I ===
-** '''Follow-up for Bosniak I cysts is not warranted'''
+* '''<span style="color:#ff0000">Follow-up for Bosniak I cysts is not warranted</span>'''
-*** Majority will grow over time; growth should not necessarily be considered a sign a malignancy
+** Majority will grow over time; growth should not necessarily be considered a sign a malignancy
-*** Transformation into a more complex cyst is rare and has been reported in only a handful of cases
+** Transformation into a more complex cyst is rare and has been reported in only a handful of cases
-** '''Intervention is only warranted if the cyst becomes symptomatic''' (i.e., bleeding, recurrent infection or pain)
+* '''<span style="color:#ff0000">Intervention is only warranted if the cyst becomes symptomatic''' (i.e., bleeding, recurrent infection or pain)
-*** Treatment options include: percutaneous management (aspiration +/- sclerotherapy) or surgery
+** Treatment options include: percutaneous management (aspiration +/- sclerotherapy) or surgery
-*** Percutaneous cyst decompression may also be considered prior to offering definitive treatment as a means to confirm that the source of symptoms are cyst-related.
+** Percutaneous cyst decompression may also be considered prior to offering definitive treatment as a means to confirm that the source of symptoms are cyst-related.
-* '''Bosniak II'''
-** '''Follow-up for Bosniak II cysts is not warranted'''
-** '''Intervention is only warranted if the cyst becomes symptomatic'''
-* '''Bosniak IIF'''
-** '''≈15% of these category IIF cysts will progress in complexity (to Bosniak category III or IV)''' over time
-** '''Should be followed with a contrast-enhanced CT scan or MRI every 6 months for the first year. Cases without progression should be followed annually for at least 5 years.'''
-* '''Bosniak III'''
-** '''Surgical excision is generally suggested'''
-*** '''Given the low metastatic potential of cystic RCC, the panel feels that reduced surgical margins and controlled cyst decompression (if required) can be performed with low risk of tumour recurrence.'''
-*** '''Likewise, due to the same reason, active surveillance and thermal-ablation therapies may also be considered as appropriate treatment alternatives in select cases'''
-* '''Bosniak IV'''
-** '''Surgical excision is generally suggested'''
-*** '''Most of these malignant cysts are thought to have low metastatic potential and thus, more conservative management may be safely considered in select cases'''
-===== '''Role of active surveillance for suspected cystic RCC''' =====
+=== Bosniak II ===
+* '''<span style="color:#ff0000">Follow-up for Bosniak II cysts is not warranted</span>'''
+* '''<span style="color:#ff0000">Intervention is only warranted if the cyst becomes symptomatic</span>'''
+=== Bosniak IIF ===
+* '''≈15% of these category IIF cysts will progress in complexity (to Bosniak category III or IV)''' over time
+* '''<span style="color:#ff0000">Should be followed with a contrast-enhanced CT scan or MRI every 6 months for the first year. Cases without progression should be followed annually for at least 5 years.</span>'''
+=== Bosniak III ===
+* '''<span style="color:#ff0000">Surgical excision is generally suggested</span>'''
+** '''Given the low metastatic potential of cystic RCC, the panel feels that reduced surgical margins and controlled cyst decompression (if required) can be performed with low risk of tumour recurrence.'''
+** '''Likewise, due to the same reason, active surveillance and thermal-ablation therapies may also be considered as appropriate treatment alternatives in select cases'''
+=== Bosniak IV ===
+* '''<span style="color:#ff0000">Surgical excision is generally suggested</span>'''
+** '''Most of these malignant cysts are thought to have low metastatic potential and thus, more conservative management may be safely considered in select cases'''
+== Role of active surveillance for suspected cystic RCC ==
 * '''The vast majority of cystic RCCs are multilocular cystic RCCs (mcRCC,)''' but all RCC subtypes may present in a predominantly cystic form. '''Cystic RCCs need to be distinguished from solid renal masses with necrotic components, which behave more aggressively.'''
@@ Line 48: / Line 52: @@
 *# '''Fast-growing nodule'''
-===== '''Thermal-ablation therapies''' =====
+== Thermal-ablation therapies ==
 * '''Given the limited data, RFA should be limited to patients with small Bosniak category III and IV cysts who are poor operative candidates and in whom active surveillance is not being considered'''
 * '''The role of cryotherapy in the management of Bosniak III or IV cysts is not well-defined,''' with only a handful of cases reported to have been treated by the approach in the literature.
-===== '''Role of renal tumour biopsy in the management of cystic lesions''' =====
+== Role of renal tumour biopsy in the management of cystic lesions ==
 * There is evidence that RTBs are significantly less informative for the diagnosis of cystic lesions than for solid ones.
 * '''It is generally felt that RTB is not diagnostic for most Bosniak III cysts, as there is minimal targetable solid component.'''
 * '''For Bosniak IV cysts, a biopsy of the solid component may be considered to confirm the presence of a malignant tumour and to help with decision-making in select cases (elderly, multiple comorbidities, unfit for treatment, etc).'''