Abnormal patterns of mucin secretion in ileal neobladder mucosa: evidence of preneoplastic lesion?

In gastric and colonic mucosa the abnormal pattern of mucin secretion has been related to an increased risk of malignant changes. The short- and long-term histologic and histochemical changes in the mucin content of the ileal mucosa have been studied in 180 biopsies from 90 male patients 6-96 months after radical cystectomy and urinary diversion via an orthotopic neobladder. Up to 3 years after surgery, histologic changes comprise a shortening of the villi and an increase in the number of goblet cells. Concomitantly, an abnormal pattern of mucin secretion, with a predominant secretion of sulfomucins, is demonstrable. After 3 years of follow-up, the mucosa progressively flattens and mucin production reduces; after 6 years, the prevalent finding is a flat, avillous epithelium without evidence of mucin secretion. There was no dysplasia or malignancies in any of the patients. The changes in the pattern of mucin production are not potential preneoplastic lesions, but represent a transient defence mechanism of the ileal mucosa exposed to urine.