High resolution endoscopy and the additional value of chromoendoscopy in the evaluation of duodenal adenomatosis in patients with familial adenomatous polyposis

Background and study aim: Duodenal polyposis occurs in approximately 90% of patients with familial adenomatous polyposis (FAP) and 5%10% develop duodenal cancer. Novel imaging techniques may improve evaluation of duodenal polyposis using the Spigelman classification. We aimed to analyze the value of high resolution endoscopy (HRE) and the additional value of chromoendoscopy in the evaluation of duodenal polyposis in FAP. Patients and methods: 43 FAP patients scheduled for surveillance endoscopy in two academic centers underwent gastroduodenoscopy with HRE forward- and side-viewing devices. After number and size of adenomas had been scored, indigo carmine 0.5% was sprayed onto the mucosa, polyps were scored again and biopsies taken from the larger lesions. Subsequently, Spigelman classifications were assessed for pre- and post-staining. Results: Before staining, a median of 16 adenomas per patient were detected compared with 21 adenomas after staining (P=0.02). Staining led to upgrading of Spigelman stage in 5/43 patients (12%). Using the side-viewing endoscope, ampullary enlargement was detected in 22 patients (51%) of whom 18 (42%) had histologically confirmed ampullary adenomas. Conclusion: HRE has raised the quality of endoscopic imaging considerably. Consequently, re-evaluation of the original Spigelman classification system seems advisable. Chromoendoscopy further increases detection of duodenal adenomas in FAP but without considerable change in Spigelman stage. Ampullary adenomas are commonly found in FAP and are best visualized using a side-viewing endoscope. Therefore, a combination of forward-viewing HRE and chromoendoscopy with side-viewing endoscopy for the periampullary region seems useful for surveillance of duodenal adenomatosis in FAP.