fundic gland polyp

PO

Definition: Fundic glandulocystic polyps (or Fundic gland polyps - FGPs) are tiny multiple sessile polyps of the acid-secreting gastric mucosa. FGPs are sessile polyps arising in the oxyntic mucosa that can be single or multiple.

Images

 Fundic gland polyp; in body/fundus; most sporadic (also PPI Rx, FAP); dilated glands lined by parietal cells

• https://twitter.com/DrAndrewRyan/status/750582418101460996

 morules in fundic gland polyp

• https://twitter.com/GeronimoJrLapac/status/1097514429829300224

Cases

 PO:399

Epidemiology

Fundic glandulocystic polyps are the most common benign polyps encountered in a surgical pathology practice.

Fundic gland polyps have been described both in a sporadic form, mainly in middle-aged females, and in a syndromic form, associated with familial adenomatous polyposis (FAP)-Gardner’s syndrome and attenuated variants (AFAP).
Fundic gland polyps occur sporadically, develop in the setting of familial adenomatous polyposis (FAP), or complicate the use of protonpump inhibitors.

Molecular biology

Sporadic polyps can contain activating beta-catenin mutations, whereas FAP-associated polyps have biallelic APC mutations.

Sporadic and FAP-associated polyps result from separate and distinct
wnt signaling pathway alterations.

FGPs developing in the setting of FAP may result in a carpet of several hundred polyps usually measuring @<@ 5 mm in diameter with a sessile base and a smooth-domed surface.

FGPs can develop and disappear within weeks.

Torsion or mechanical traction resulting in auto-amputation may cause some polyps to disappear.

Microscopy

FGPs are localized hyperplastic expansions of the deep glandular compartment ofthe oxyntic mucosa. The overlying pits appear shortened or absent.

They contain cystically dilated, irregularly deformed oxyntic glands with or without glandular proliferations, increased smooth muscle in the lamina propria, and a lack of hyperplastic foveolar cells.

The glands are lined by normal oxyntic cells, including a mixture of parietal, chief, and mucous neck cells.

The glands appear almost to be tacked onto the surface of a normal or slightly atrophic mucosa.

FGPs probably develop from the progressive dilation and infolding of glandular buds to produce irregular tortuous glands and microcysts.

These lesions are generally benign. However, in the setting of FAP, they may contain areas of dysplasia.

Fundic gland polyps (FGPs) share the same histology, characterised by superficial and deep cystic dilatations, shortened gastric pits, with an inconspicuous lamina propria.

Evolution - Prognosis

Fundic gland polyps (FGPs) have been for a long time described as innocuous lesions, but some recent reports have shown that FGPs may harbour dysplastic foci and ultimately (particularly syndromic polyps) gastric cancer. Factors influencing their genesis are unknown.

Physiopathology

A circulating factor in FAP patients has been postulated and a role of female hormones has been suggested for sporadic FGPs.

Whereas patients with sporadic FGPs have normal basal acid output, normal fast serum levels of gastrin and pepsinogen I, the role of gastrin seems crucial for the development of cystic changes in flat body-fundus mucosa, and for the appearance of FGPs in patients with Zollinger-Ellison syndrome.

The nature of FGPs is still debated: some have interpreted them as hamartomatous lesions, others as a peculiar form of hyperplastic polyp.

Etiology

 Proton pump inhibitors (PPI) intake is the strongest risk factor associated with the presence of FGPs. (21127978)

 somatic mutations of CTNNB1 coding for beta-catenin in sporadic fundic gland polyps (11238048)

 germline mutations of APC in Gardner syndrome

 A role of H. pylori induced gastritis has been excluded.

• Actually, patients with both sporadic and syndromic FGPs appear consistently free from H. pylori colonisation, again for an unknown factor(s).

See also

 gastric polyps

• gastric hyperplastic polyp

References

 Fundic gland polyps and association with proton pump inhibitor intake: a prospective study in 1,780 endoscopies. Zelter A, Fernández JL, Bilder C, Rodríguez P, Wonaga A, Dorado F, Galich M, Viola LA. Dig Dis Sci. 2011 Jun;56(6):1743-8. PMID: 21127978

 Proton pump inhibitors and an emerging epidemic of gastric fundic gland polyposis. Freeman HJ. World J Gastroenterol. 2008 Mar 7;14(9):1318-20. PMID: 18322941

 Increased risk of fundic gland polyps during long-term proton pump inhibitor therapy. Jalving M, Koornstra JJ, Wesseling J, Boezen HM, DE Jong S, Kleibeuker JH. Aliment Pharmacol Ther. 2006 Nov 1;24(9):1341-8. PMID: 17059515

 Fundic gland polyps are not induced by proton pump inhibitor therapy. Vieth M, Stolte M. Am J Clin Pathol. 2001 Nov;116(5):716-20. PMID: 11710689

 Proton pump inhibitor-associated gastric polyps: a retrospective analysis of their frequency, and endoscopic, histologic, and ultrastructural characteristics. Choudhry U, Boyce HW Jr, Coppola D. Am J Clin Pathol. 1998 Nov;110(5):615-21. PMID: 9802346

 Fundic gland polyps: three other case reports suggesting a possible association with acid suppressing therapy. Van Vlierberghe H, De Vos M, De Cock G, Cuvelier C, Elewaut A. Acta Gastroenterol Belg. 1997 Jul-Sep;60(3):240-2. PMID: 9396183

 Hyperplastic fundic gland polyp of the stomach. Hanada M, Takami M, Hirata K, Kishi T, Nakajima T. Acta Pathol Jpn. 1983 Nov;33(6):1269-77. PMID: 6670558