Subepithelial basement membrane thickness in patients with normal colonic mucosal appearance in colonoscopy: results from southern Turkey.

AIM

Our aims were to determine the normal limits of subepithelial basement membrane (SEBM) thickness in order to more accurately diagnose collagenous colitis in the population from southern Turkey and to investigate into links between SEBM thickness and age, and sex.

METHODS

The study included 100 patients (mean age 50.0+/-13.3 years; male, 34; female, 66) with miscellaneous gastrointestinal symptoms, and normal colonic mucosal appearance in colonoscopic evaluation. Biopsies were taken from five different regions of the colon. SEBM was measured with a calibrated eyepiece on specimens prepared with specific stains for collagen. Intensity of inflammatory cells was graded semiquantitatively. Differences in SEBM thickness among the different colon regions, and relationships between SEBM thickness and age, sex, and density of inflammatory cells were statistically evaluated.

RESULTS

The cecum and rectum showed the largest amounts of infiltrate. None of the specimens showed histologic findings of collagenous colitis. The SEBM thicknesses measured for each case ranged from 3-20 microm. The biggest thickness was observed in rectal mucosa (median value: 10 microm). Cecum and ascending colon showed similar SEBM thickness (median value: 5 microm). SEBM thickness was not correlated with patient age or sex, but was positively correlated with the intensity of inflammatory cells in each colon segment.

CONCLUSION

In this patient group from southern Turkey, SEBM was thickest in the rectum. Our results indicate that, in this population, SEBM thickness is not correlated with age or sex, but is positively correlated with severity of inflammation. The findings also support the concept that measuring SEBM thickness at one segment in the colon is inadequate and may be misleading.