Morphology and natural history of familial adenomatous polyposis-associated dysplastic fundic gland polyps

• Published in: Histopathology Vol. 65; no. 3; pp. 353 - 362
• Main Authors: Arnason, Thomas, Liang, Wen-Yih, Alfaro, Eduardo, Kelly, Paul, Chung, Daniel C, Odze, Robert D, Lauwers, Gregory Y
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.09.2014; Wiley Subscription Services, Inc
• Subjects: Adenomatous Polyposis Coli - etiology; Adenomatous Polyposis Coli - pathology; Adenomatous Polyps - etiology; Adenomatous Polyps - pathology; Adolescent; Adult; Aged; Aged, 80 and over; Cohort Studies; Disease Progression; dysplasia; familial adenomatous polyposis; Female; fundic gland polyp; Gastric Fundus - pathology; Gastric Mucosa - pathology; Humans; Male; Middle Aged; Retrospective Studies; Risk Factors; stomach; Stomach Neoplasms - etiology; Stomach Neoplasms - pathology; Young Adult; dysplasia; fundic gland polyp; stomach; familial adenomatous polyposis
• ISSN: 0309-0167; 1365-2559; 1365-2559
• DOI: 10.1111/his.12393

Aims Most patients with familial adenomatous polyposis (FAP) develop gastric fundic gland polyps, with many displaying low‐grade dysplasia. This study evaluates the natural history and morphological phenotype of dysplasia in FAP‐associated fundic gland polyps. Methods and results Patients with FAP and dysplastic fundic gland polyps (n = 24) were identified. Twenty‐two of 24 FAP‐associated dysplastic fundic gland polyps showed a gastric phenotype and two had mixed phenotype. During a mean 6.1‐year follow‐up (range 0.8–12.6 years) and 5.7 endoscopies (range 2–22), one patient (4%) was diagnosed with a fundic gland polyp with high‐grade dysplasia, while 23 patients (96%) in this cohort had either no dysplasia or persistent low‐grade dysplasia. Contemporary patients with sporadic fundic gland polyps with low‐grade dyplasia had similar morphology and outcomes to the FAP‐associated fundic gland polyp cohort. Dysplasia in fundic gland polyps (FAP‐associated and sporadic) was associated less frequently with intestinal phenotype, high‐grade dysplasia and the finding of concurrent or subsequent carcinoma compared to contemporary patients with sporadic gastric dysplasia not occurring in fundic gland polyps. Conclusions This cohort of patients with FAP‐associated dysplastic fundic gland polyps rarely developed high‐grade dysplasia and gastric adenocarcinoma was absent.