I read with interest the recent article by Pardi1 on collagenous colitis. In spite of the increased awareness of this condition among clinicians and pathologists, collagenous colitis, described by Lindström2 in 1976 and characterised by a thick subepithelial collagen band3 (>10 μm), is still underdiagnosed in many parts of the world. This is partly due to different diagnostic criteria and to the fact that the lower border of the band is not well demarcated. Therefore, correct estimation of the thickness of this band is not always reliable.

To compare the efficacy of the different staining methods used in measuring the thickness of the collagen layer in collagenous enterocolitis, including tenascin expression,4 we examined histological sections of 245 endoscopic biopsies from 199 symptomatic patients (140 female and 59 male) referred to the endoscopy unit …