Fluorescent visualisation of collagenous band: an improved technique for use in the diagnosis of collagenous colitis

Aims: Collagenous colitis (CC) is underdiagnosed and causes chronic diarrhoea in the elderly; it is characterised by a thick CB (>10m). We undertook this study to determine if the newly described technique, examination of H&E sections under fluorescent light (FH&E) is superior to routine methods for measuring the subepithelial collagen band (CB) depth.

Methods: Employing Image Analysis software, CB thickness was measured on identical areas of serial 5m sections using different staining (H&E and van Gieson) and illumination techniques (FH&E). Coded colonic biopsies from patients with chronic diarrhoea were studied including 14 coeliac disease and 7 non-coeliac patients (CC >10m, equivocal 7–10m, normal <7m).

Results: CB depth measurements:- H&E 5.2m (range 1.7–7.2m; SD 3.7m); van Gieson 4.4m (1.2–11.0; 2.9); FH&E 7.0m (2.0–21.1; 4.8). Of the 21 biopsies 6>7m of which 4 were<10m on H&E but were >10m on FH&E and are reclassified as definite CC.

Conclusions: FH&E dramatically enhances the visibility of the CB enabling a diagnosis of CC to be confirmed or refuted. This technique is cheap; it uses standard equipment and is applicable to new and archive H&E sections.