squamous cell carcinoma ( scc ) after ileal pouch - anal anastomosis ( ipaa ) for ulcerative colitis ( uc ) is very rare [ 1 , 2 ] .
scc is extremely sensitive to chemoradiation therapy ( crt ) , but an ileal pouch is generally considered a contraindication to radiotherapy .
few cases of scc in ipaa patients have been described in the literature , with variable treatments and unpredictable outcomes .
we report the successful management of an scc of the anal transitional zone ( atz ) after ipaa and systematically review the literature for ipaa - related scc .
the patient has had good functional outcomes but suffered from several episodes of pouchitis . in 2014 ,
he was seen at the outpatient clinic due to a nodule in the anal canal which had rapidly increased in size ( fig .
the patient underwent flexible pouchoscopy and examination under general anaesthesia with biopsies , pelvis mri ( fig . 2a 
findings were consistent with a moderately well - differentiated scc of the atz , with no evidence of distant disease ( t1n0m0 ) .
we performed a systematic review of the literature to identify scc arising from the pouch or from the atz of uc patients .
inclusion criteria were unequivocal diagnosis of scc that can be reasonably considered as de novo carcinoma , diagnosis of uc , and availability of adequate information .
studies including patients with conditions other than uc were only included if uc patients were identifiable .
available data of all patients operated on with ipaa between 1978 and 2016 were evaluated .
keywords and medical subject headings ( mesh ) used were :  restorative proctocolectomy , 
 ulcerative colitis ,   squamous cell carcinoma ,   pouch ,   ipaa ,  and  scc . 
the patient has had good functional outcomes but suffered from several episodes of pouchitis . in 2014 ,
he was seen at the outpatient clinic due to a nodule in the anal canal which had rapidly increased in size ( fig .
the patient underwent flexible pouchoscopy and examination under general anaesthesia with biopsies , pelvis mri ( fig . 2a 
findings were consistent with a moderately well - differentiated scc of the atz , with no evidence of distant disease ( t1n0m0 ) .
we performed a systematic review of the literature to identify scc arising from the pouch or from the atz of uc patients .
inclusion criteria were unequivocal diagnosis of scc that can be reasonably considered as de novo carcinoma , diagnosis of uc , and availability of adequate information .
studies including patients with conditions other than uc were only included if uc patients were identifiable .
available data of all patients operated on with ipaa between 1978 and 2016 were evaluated .
keywords and medical subject headings ( mesh ) used were :  restorative proctocolectomy ,   ulcerative colitis ,   squamous cell carcinoma ,   pouch ,   ipaa ,  and  scc .
the multidisciplinary meeting recommendation for the present case was to proceed with the conventional radiation dose to the expected effects on the ileal pelvic pouch and to the nodal spread .
he received a single administration of mitomycin ( 13.5 mg ) and daily capecitabine tablets during the course of radiotherapy ( 1,300 mg / day ) .
4 ) and only suffered from pain and ulceration to the skin during crt . at the 24-month follow - up , the patient has acceptable function , no incontinence nor urgency , and good control of flatus .
on endoscopy , the mucosa of the pouch was healthy , but a stricture with inflammation was noticed at the pouch inlet ( fig .
which did not fit inclusion criteria , only 5 papers reporting on 7 scc were available for analysis ( table 1 ) . when matching the series of several centres , including a total of 5,136 patients , only 3 cases of scc
have been observed over time , corresponding to a cumulative incidence of 0.058% 25 years after ipaa [ 3 , 4 , 5 , 6 , 7 ] .
five scc developed from either the atz or rectal cuff [ 7 , 8 , 9 ] and 2 from the mucosa of the pouch [ 10 , 11 ] .
out of 2 patients with scc of the pouch , 1 with scc close to the ileal pouch inlet was unsuitable for crt and died 6 months after pouch excision   and 1 had pouch excision followed by crt ( mitomycin c , 5-fluorouracil , and local radiotherapy ) with no response .
only 1 paper reported crt for ileal pouch - related scc arising from the rectal cuff .
the patient was a 47-year - old woman , who received 5-fluorouracil , mitomycin c , and external beam radiation therapy and appeared to have a clinical response .
several cases of ipaa - related cancers have been reported [ 1 , 12 , 13 ] . a systematic review of the literature suggested that the cumulative risk of  de novo  ipaa - related cancer is 0.33%   after removing dubious cases , meaning those that should have been considered either persistence or recurrence of previously treated cancer .
dysplasia or cancer on the colectomy specimen is the strongest predictor of ipaa - related cancer [ 1 , 4 , 7 ] .
patients with these features are 8 times more likely of developing ipaa - related cancer , irrespective of mucosectomy .
seven [ 7 , 8 , 9 , 10 , 11 ] ipaa - related scc have been described , of which 5 developed from either the atz or rectal cuff [ 7 , 8 , 9 ] and 2 from the mucosa of the ileal pouch [ 10 , 11 ] ( table 1 ) .
dysplasia on the specimen is considered a risk factor for scc , but metaplasia of the ileal pouch could underlie scc , especially squamous metaplasia [ 10 , 11 ] .
this is poorly addressed in uc , whereas more attention is paid to the detection of dysplasia for subsequent cancer concern and surveillance .
crt is the treatment of choice for anal scc , but it can also achieve complete response in up to 66% of patients with rectal scc . it is largely agreed that pelvic irradiation is contraindicated in patients with a pelvic ileal pouch because of the predictable risk of radiation enteritis , which is likely to cause pouch failure due to structural damage to the mucosa and body of the reservoir .
however , no studies have addressed the actual role of radiotherapy in these patients , and these considerations might be even more interesting under the light of newer treatment regimens .
one paper reported crt   for an early tumour discovered on routine anal biopsy , and no description is provided concerning the stage [ 8 , 11 ] .
moreover , the patient suffered from poor function , with seepage and 20 bowel movements per day . when acute toxicity settled down , good function was restored , but the patient required diphenoxylate hydrochloride and atropine sulfate 8 times daily .
no data are available concerning the long - term effects of crt and treatment outcomes .
the largest series on the topic suggested that patients with rectal cancer can have ipaa , but radiotherapy before pouch surgery impairs subsequent function and increases failure rates .
european guidelines currently recommend that radiotherapy should precede pouch surgery and should be avoided after ipaa , even acknowledging that the evidence for that assumption is low . indeed ,
scc located in the pouch body seem to be more aggressive and might be difficult to treat with radiation therapy .
out of 2 patients with scc occurring in the ileal pouch , 1 with scc close to the ileal pouch inlet was unsuitable for crt and died 6 months after pouch excision , and 1 was approached with pouch excision followed by crt ( mitomycin c , 5-fluorouracil , and local radiotherapy ) but had no response .
we were able to manage an scc of the ileal pouch by means of a crt protocol that achieved complete response , without the adverse effects of radiotherapy on pouch function .
avoiding excessive worsening of function is important , especially in frail patients , who may suffer from serious dehydration and electrolyte loss secondary to increased ileal pouch - anal output .
the early outcome was acceptable , and no particular measures were required apart from loperamide administration . in the long term , the patient did not need any surgical treatment , which is associated with a doubled risk of failure and dysfunction over time in ipaa [ 19 , 20 ] .
however , the decision on how to treat patients with scc and anal cancer of the pelvic pouch needs to be individualized , and patients and their relatives should participate in the decision - making process .
scheduled follow - up of the pouch is usually not recommended in uc patients without risk factors for cancer .
indeed , the risk of colorectal cancer arising from the rectal remnant or atz is lower after ipaa than the lifetime risk of cancer in the general population .
however , endoscopic follow - up and surveillance after ipaa probably need to be further elucidated [ 13 , 21 ] because scc may occur at some point even in patients with no known risk factor .
early detection is the key to preserve the pouch in patients who develop ipaa - related scc .
crt according to our regimen could be considered in scc arising from the rectal cuff or atz .
this could be the first - line approach in anal scc after ipaa , but it could also be advocated for other types of cancer , hopefully increasing the success rates and survival .
metaplasia of the pouch might play a role in scc , but this remains to be further elucidated .
patients with pelvic pouches receiving crt should be followed up with scheduled long - term appointments including pouchoscopy to diagnose recurrence and late adverse effects of radiation .
written informed consent for patient information and images to be published was provided by the patient .
 backgroundfew cases of pouch - related cancers have been reported in ulcerative colitis ( uc ) , and squamous cell carcinoma ( scc ) is very rare.methoda systematic review of the literature was performed to identify all unequivocal cases of pouch - related scc in uc patients.resultseight cases of scc developing after ileal pouch - anal anastomosis ( ipaa ) have been observed since 1978 . 
 two arose from the pouch mucosa and 6 from below . 
 the pooled cumulative incidence of scc is below 0.06% after ipaa . 
 many patients had neoplasia on the preoperative specimen , but squamous metaplasia of the pouch or anorectal mucosa may have an important role in scc . 
 these patients are rarely offered chemoradiation therapy and the outcome is poor . selected patients with scc located close to the pouch outlet can be treated with chemoradiation prior to consideration of surgery and salvage their pouch . 
 a chemoradiation regimen is suggested to avoid pouch excision in these patients.conclusionsscc is rare after pouch surgery but associated with extremely poor survival . 
 very low scc can be managed with chemoradiation treatment , preserving the pouch and avoiding surgery , even in older patients . 
 the role of pouch metaplasia , surveillance frequency , and treatment modalities after ipaa need further studying . 
Introduction
Materials and Methods
Short Report
Systematic Review
Data Search
Results
Discussion
Conclusion
Statement of Ethics
Disclosure Statement
Author Contributions