Cancer risk in IBD: how to diagnose and how to manage DALM and ALM

Abstract

The risk of developing neoplasia leading to colorectal cancer is significantly increased in ulcerative colitis (UC) and most likely in Crohn's disease. Several endoscopic surveillance strategies have been implemented to identify these lesions. The main issue is that colitis-associated neoplasms often occurs in flat mucosa, often being detected on taking random biopsies rather than by identification of these lesions via endoscopic imaging. The standard diagnostic procedure in long lasting UC is to take four biopsies every 10 cm. Image enhancement methods, such as chromoendoscopy and virtual histology using endomicroscopy, have greatly improved neoplasia detection rates and may contribute to reduced random biopsies by taking targeted "smart" biopsies. Chromoendoscopy may effectively be performed by experienced endoscopists for routine screening of UC patients. By contrast, endomicroscopy is often only available in selected specialized endoscopic centers. Importantly, advanced endoscopic imaging has the potential to increase the detection rate of neoplasia whereas the interplay between endoscopic experience and interpretation of histological biopsy evaluation allows the physician to make a proper diagnosis and to find the appropriate therapeutic approach. Colitis-associated intraepithelial neoplasms may occur in flat mucosa of endoscopically normal appearance or may arise as dysplasia-associated lesion or mass (DALM), which may be indistinguishable from sporadic adenomas in healthy or non-colitis mucosa [adenoma-like mass (ALM)]. The aim of this review was to summarize endoscopic and histological characteristics of DALM and ALM in the context of therapeutic procedures.

Keywords: Adenoma-like mass; Cancer; Chromoendoscopy; Colitis; Confocal laser endomicroscopy; Crohn’s disease; Dysplasia; Dysplasia-associated lesion or mass; Endomicroscopy; Endoscope-based confocal laser endomicroscopy; Endoscopy; Inflammatory bowel disease; Integrated confocal laser endomicroscopy; Narrow band imaging; Probe-based confocal laser endomicroscopy; Ulcerative colitis.

Figure 1

Visualization of a dysplasia-associated lesion or mass after topical application of indigo carmine. Surface analysis revealed a Kudo pit pattern 3L.

Figure 2

High-resolution standard white light endoscopic image of an adenoma-like mass in a patient with long standing ulcerative colitis. Surface of the polyp is irregular and shows fibrin plaques. Histopathological analysis revealed high-grade intraepithelial neoplasia.

Figure 3

Multiple inflammatory polyps in chronic ulcerative colitis. Image was recorded using the Pentax endomicroscope (EC-3870CIFK). Note the confocal lens at the 7 o’clock position.

Figure 4

Chromoendoscopy with indigo carmine allows distinct surface analysis and demarcation of subtle lesions in long standing ulcerative colitis.

Figure 5

Fluorescein-guided confocal laser endomicroscopy (iCLE, Pentax, Tokyo, Japan) of dysplasia-associated lesion or mass. Endomicroscopy visualizes tubular architecture and enlarged cells with depletion of goblet cells. The shape and size of the crypts is irregular, and leakage, demonstrated by the extravasation of fluorescein, is visible.

Figure 6

Fluorescein guided confocal laser endomicroscopy of adenoma-like mass (ALM; pCLE, Cellvizio, Mauna Kea Technologies, Paris, France). Endomicroscopy shows villous transformation of colonic architecture and depletion of goblet cells indicating adenomatous tissue.

Figure 7

Histopathological image of dysplasia-associated lesion or mass with low-grade intraepithelial neoplasia in a patient with quiescent ulcerative colitis (A). Panel B illustrates colitis-associated cancer with submucosal invasion.