Some of the rare complications reported in patients with an ileopouch anal anastomosis (IPAA) after coloectomy for chronic ulcerative colitis are dysplasia and carcinoma.
The supposed pathway is for the ileal pouch mucosa to go through adaptational changes then is to progress through the phases of chronic pouchitis, dysplasia and subsequently to adenocarcinoma.
In many of these studies however, the dysplasia - cancer sequence is inconclusive since the carcinoma might have developed from the ileal mucosa itself or from residual viable rectal mucosa left behind.
Dr Hulten and colleagues from Sweden undertook a study to examine the long-term ileal mucosal adaptation patterns and the incidence and grading of dysplasia in the ileal pouch mucosa in patients previously operated on for ulcerative proctocolitis.
The research group included a total of 45 patients who had been operated on with an IPAA (25 males/20 females).
The participants had a median age of 54 years (range 34-76) and were invited for clinical examination and pouch endoscopy including mucosal biopsies.
The duration of their colitis until surgery was median 6 years and the time median interval from start of disease until time of follow up 24.8 years.
The researchers recruited 3 independent pathologists from 2 different centres who reviewed sequential mucosal biopsies taken from separate sites of the pouch for dysplasia and mucosal adaptation patterns.
|Dysplastic transformation within the ileal pouch mucosa in patients operated for ulcerative proctocolitis is rare even after a long follow-up|
The 2 pathologists from 1 centre observed the type C pattern with a severe inflammation in lamina propria together with severe atrophy of villi, sometimes with ulceration and granulation tissue 33.3% of patients.
The third pathologist reported the same findings in 24.4% of patients.
As regards dysplasia the researchers recorded that 1 pathologist group evaluated 4.4% cases as low-grade dysplasia while the third pathologist considered 1 of these cases as indefinite for dysplasia and 1 as reactive.
In this respect, there was full agreement between the 2 centres in 95.6% of cases.
The pathologists diagnosed neither high-grade dysplasia nor invasive carcinoma.
Dysplastic transformation within the ileal pouch mucosa in patients operated for ulcerative proctocolitis is rare even after a long follow-up.
Dr Hulten commented, "These results are reassuring for both patients and surgeons."
"There seem to be no solid grounds to support routine surveillance for dysplasia in the ileal pouch mucosa in these patients."
"The surveillance for neoplastic changes in the remaining muscular/epithelial cuff is a separate issue however."