Sporadic Fundic Gland Polyps With Low-Grade Dysplasia: A Large Case Series Evaluating Pathologic and Immunohistochemical Findings and Clinical Behavior

Abstract

Objectives: Fundic gland polyps (FGPs) occur in two clinicalFundic gland polyps (FGPs) are the most common type of gastric polyp. 1,2 They typically occur in the body and fundus of the stomach and are composed of cystically dilated oxyntic glands lined by attenuated chief, parietal, and mucous neck cells. The polyp surface is lined by gastric foveolar epithelium. FGPs occur in two different clinical settings, sporadic and syndromic (familial adenomatous polyposis, or FAP).Sporadic FGPs have been reported in 0.8% to 1.9% of patients who undergo upper endoscopy. 3,4 They are slightly more common in women than in men, and their occurrence has been associated with prolonged use of proton pump inhibitors (PPIs). 3,4 In sporadic FGPs, low-grade epithelial dysplasia has been described, but its prevalence is extremely rare (approximately 1%). 5 Syndromic FGPs arise in patients with FAP, have been reported in 12.5% to 84% of patients with FAP, occur in a younger age group, and equally affect men and women. 4,[6][7][8][9][10][11][12][13] Epithelial dysplasia is more common Upon completion of this activity you will be able to:• describe the features of sporadic fundic gland polyps with low-grade dysplasia in terms of the incidence of these polyps, patient characteristics, and pathologic and immunohistochemical findings.• compare and differentiate between fundic gland polyps with low-grade dysplasia in the sporadic and syndromic setting.The ASCP is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The ASCP designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 Credit ™ per article. Physicians should claim only the credit commensurate with the extent of their participation in the activity. This activity qualifies as an American Board of Pathology Maintenance of Certification Part II Self-Assessment Module.The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose.Exam is located at www.ascp.org/ajcpcme.

Comparison of dysplastic fundic gland polyps in patients with and without familial adenomatous polyposis

“…Dysplasia in d‐FGPs is generally described as occurring with surface foveolar and glandular mucous neck cells, with parietal and chief cells being uninvolved . In rare instances, dysplasia of parietal cells was hinted at but not definitely observed in our study, given the focal dysplasia within non‐foveolar, non‐mucous neck cells (Figure F) and possible nuclear β‐catenin staining within parietal cells (Figure C), although this was difficult to evaluate on IHC sections.…”

“…The development of malignancy in FGPs is extremely rare, with very few cases having been reported in the literature; it has been reported that FAP patients do not have an increased risk of gastric carcinoma . The adenomatous polyposis coli (APC)–β‐catenin pathway has been implicated in the development of dysplastic (and non‐dysplastic) FGPs in FAP patients, and immunohistochemistry (IHC) for β‐catenin can accordingly be positive in dysplastic nuclei …”

“…Although dysplasia appears to be more likely to occur in syndromic FGPs, multiple authors have reported d‐FGPs in non‐syndromic patients as well . This subset of d‐FGPs, which also show APC–β‐catenin abnormalities, has undergone scrutiny in recent years, but is less well studied overall.…”

“…9 The adenomatous polyposis coli (APC)b-catenin pathway has been implicated in the development of dysplastic (and non-dysplastic) FGPs in FAP patients, 6 and immunohistochemistry (IHC) for b-catenin can accordingly be positive in dysplastic nuclei. [10][11][12] Although dysplasia appears to be more likely to occur in syndromic FGPs, multiple authors have reported d-FGPs in non-syndromic patients as well. 6,8,[12][13][14] This subset of d-FGPs, which also show APC-b-catenin abnormalities, [13][14][15] has undergone scrutiny in recent years, but is less well studied overall.…”

“…[10][11][12] Although dysplasia appears to be more likely to occur in syndromic FGPs, multiple authors have reported d-FGPs in non-syndromic patients as well. 6,8,[12][13][14] This subset of d-FGPs, which also show APC-b-catenin abnormalities, [13][14][15] has undergone scrutiny in recent years, but is less well studied overall. Having noticed that our patient population appears to be enriched for non-syndromic d-FGPs, we undertook this study to compare clinical and pathological characteristics across syndromic and non-syndromic cases.…”