Fundic Gland Polyps

Slide 1 · Fundic gland polyps

Morphology, pathogenesis, syndromic associations and clinicopathologic interpretation

Gastric pathology

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

Localize fundic gland polyps within gastric oxyntic mucosa.

Explain sporadic, proton pump inhibitor–associated and inherited settings.

Recognize the defining microscopic composition and limited inflammation.

Contrast fundic gland polyps with hyperplastic polyps and adenomas.

Interpret dysplasia risk according to the clinical context.

Slide 3 · Gastric polyps are a heterogeneous finding

A gastric polyp projects above adjacent mucosa; This describes a growth pattern, not a single diagnosis.

Polyps, nodules or masses in up to 5% of upper gastrointestinal endoscopies.

Histologic type—not polypoid appearance alone—establishes the relevant biological interpretation.

Interpretation

A raised mucosal lesion may reflect epithelial growth, inflammation, ectopia or neoplasia.

Slide 4 · Mechanisms behind a raised gastric lesion

Epithelial / stromal hyperplasia

Inflammation or repair

Ectopic tissue

Neoplastic growth

Alternative mechanisms — not successive stages of the same process.

Slide 5 · Three epithelial polyp patterns to separate

Pattern

Decisive histologic clue

Fundic gland polyp

Cystically dilated oxyntic glands

Hyperplastic / inflammatory polyp

Elongated, irregular foveolar glands with edema / inflammation

Gastric adenoma

Dysplastic glandular epithelium

Slide 6 · Regional gastric anatomy determines the gland type

Fundus

Body

Antrum

Regional schematic

Fundus and body contain well-developed oxyntic glands.

Antrum is a major source of gastrin-producing G cells.

Fundic gland polyps occur in the body and fundus.

Slide 7 · The body and fundus contain oxyntic glands

Schematic — not a histologic specimen

Parietal cells produce gastric acid.

Chief cells produce and secrete digestive enzymes.

This normal glandular repertoire is retained in fundic gland polyps.

Slide 8 · Gastric epithelial lineages have different roles

Lineage

Role in the source

Diagnostic relevance

Parietal cell

Secretes gastric acid

Present in fundic gland polyp lining

Chief cell

Produces digestive enzymes

Present in fundic gland polyp lining

Foveolar mucus cell

Mucus-secreting surface/pit lineage

Also lines polyp glands

Antral G cell

Secretes gastrin

Links reduced acid output to gastrin response

Slide 9 · Gastric anatomy links gastrin and acid production

Antrum: G cells

Gastrin secretion

Body / fundus: Parietal cells

Gastric acid

Antrum and oxyntic mucosa have distinct physiologic roles.

Slide 10 · Normal architecture as a histologic reference

Schematic — not a histologic specimen

Surface and foveolar epithelium overlie gastric glands.

Body/fundus glands contain parietal and chief cells.

A cystically expanded gland becomes conspicuous against this baseline.

Slide 11 · Fundic gland polyp: A tissue-based definition

Schematic — not a histologic specimen

A smooth, well-circumscribed lesion of gastric body or fundus.

Microscopically, irregular glands are cystically dilated.

Lining comprises parietal, chief and foveolar mucus cells.

Slide 12 · Three clinical contexts, one characteristic morphology

Sporadic occurrence

Proton pump inhibitor association

Inherited APC or MUTYH setting

These are contexts, not a progression; Medication association can occur within sporadic disease.

Slide 13 · Sporadic lesions are not synonymous with hereditary disease

Sporadic

Fundic gland polyps can occur without a specified inherited predisposition.

Sporadic prevalence has risen with widespread proton pump inhibitor use.

Syndromic

Fundic gland polyps also occur with germline APC mutations.

Germline MUTYH variants are another inherited association.

Slide 14 · Proton pump inhibitor exposure is a major association

Increased prevalence of sporadic fundic gland polyps to greater proton pump inhibitor use.

The drug association has a defined physiologic pathway rather than simply co-occurring with a polyp.

The association should be interpreted separately from inherited APC or MUTYH predisposition.

Interpretation

Medication history informs etiologic context; Tissue morphology defines the polyp.

Slide 15 · Proton pump inhibitors suppress acid production

Proton pump inhibitor

Reduced parietal-cell acid output

Feedback response

Inhibited acid production as the first step in the pathway.

Slide 16 · Reduced acid output increases gastrin secretion

Acid production

Physiologic feedback

Gastrin secretion

Increased gastrin is a response to pharmacologic acid suppression.

This step links a luminal functional change to glandular growth in the stomach.

Slide 17 · Gastrin supports oxyntic gland growth

Increased gastrin

Growth of oxyntic glands

Fundic gland polyp association

The source connects hypergastrinemia to oxyntic gland growth; Do not equate growth with dysplasia.

Slide 18 · The PPI–gastrin–oxyntic growth sequence

PPI treatment

Acid secretion decreases

Gastrin secretion increases

Oxyntic gland growth

Pathogenesis diagram — supported by Robbins 11e; No quantitative effect size is claimed.

Slide 19 · A growth mechanism is not a cancer-risk estimate

Mechanistic association

Acid suppression produces a gastrin-mediated growth response.

The resulting polyp remains an oxyntic gland lesion.

Risk interpretation

Robbins does not assign a significant neoplastic risk to sporadic, including PPI-associated, polyps.

The hereditary setting requires separate evaluation.

Slide 20 · Inherited susceptibility is a distinct etiologic route

Fundic gland polyps also occur with inherited cancer-predisposition syndromes.

Robbins specifically names germline APC and MUTYH mutations.

The importance of recognizing syndromic context is the possibility of dysplasia in FAP-associated lesions.

Slide 21 · APC connects fundic gland polyps with FAP

Germline APC mutation

Familial adenomatous polyposis

Possible fundic gland polyps

Dysplasia may occur

The FAP-associated dysplasia statement is explicit in the supplied source.

Slide 22 · MUTYH is an inherited DNA repair association

What the source states

MUTYH is a DNA repair gene.

Germline MUTYH variants occur in a subset of individuals with fundic gland polyps.

Interpretive boundary

Presence of a polyp alone does not prove a MUTYH-associated syndrome.

The excerpt does not quantify MUTYH-specific dysplasia risk.

Slide 23 · Genetic background cannot be read from polyp shape

Endoscopic appearance

Smooth surface

Body/fundus location

Single or multiple

Inherited status

Requires the clinical/genetic context

Not assigned by gross appearance alone

Influences concern about dysplasia

Slide 24 · Location is a practical morphologic anchor

Fundus

Body

Antrum

Regional schematic

Classic fundic gland polyps are centered in the gastric body and fundus.

Location aligns with parietal- and chief-cell–rich oxyntic mucosa.

A lesion at another site warrants reassessment of the full morphologic pattern.

Slide 25 · Typical external contour is smooth

Smooth mucosal elevations — schematic

Not a patient endoscopy image

The mucosal surface is smooth rather than eroded in the classic description.

A visually bland contour is compatible with a fundic gland polyp.

Surface appearance cannot replace histologic typing.

Slide 26 · Fundic gland polyps are well circumscribed

Smooth mucosal elevations — schematic

Not a patient endoscopy image

A discrete, well-circumscribed mucosal lesion.

The contour reflects a localized polyp rather than a diffuse rugal process.

The microscopic architecture, not the border alone, supplies specificity.

Slide 27 · Polyp multiplicity is variable

Single lesion

Compatible with fundic gland polyp

Does not establish sporadic status

Multiple lesions

Also compatible with fundic gland polyps

Prompts attention to PPI use and inherited context

Slide 28 · What gross examination can and cannot establish

Gross/endoscopic observation

Supported interpretation

Body or fundus

Consistent anatomic compartment

Smooth surface

Consistent with classic fundic gland polyp

Discrete circumscription

Supports localized polypoid lesion

One versus several polyps

Both patterns possible; Etiology not settled

Surface alone

Insufficient to assess dysplasia

Slide 29 · Cystic dilatation is the core microscopic feature

Schematic — not a histologic specimen

Glandular lumina are enlarged, often conspicuously.

Dilatation is a defining architectural clue rather than evidence of tissue invasion.

Cystic change must be interpreted with gland type and inflammation.

Slide 30 · The expanded glands are also irregular

Schematic — not a histologic specimen

Glands vary in shape instead of remaining uniformly narrow.

Irregular cystic spaces alter the distribution of oxyntic mucosal glands.

These changes create the recognizable low-power pattern.

Slide 31 · Three epithelial lineages may line the cysts

Lining cell type

Relevant feature

Parietal cells

Oxyntic, acid-producing lineage

Chief cells

Oxyntic, enzyme-producing lineage

Foveolar mucus cells

Gastric mucus-secretory lineage

Slide 32 · Parietal cells confirm oxyntic differentiation

Schematic — not a histologic specimen

Parietal cells belong to normal body/fundus gland mucosa.

They may line the dilated irregular glands of a fundic gland polyp.

Their presence helps relate the lesion to oxyntic tissue.

Slide 33 · Chief cells contribute a second oxyntic lineage

Schematic — not a histologic specimen

Chief cells normally produce digestive enzymes.

They are among the cells lining the glandular spaces of a fundic gland polyp.

Thus the lesion is not merely foveolar mucous-cell hyperplasia.

Slide 34 · Foveolar mucus cells complete the lining pattern

Schematic — not a histologic specimen

Foveolar mucus cells may line the cystically dilated glands.

The combination of foveolar and oxyntic lineages is more informative than cysts alone.

This mixed lining should be assessed together with the stromal background.

Slide 35 · Inflammation is absent or minimal in typical lesions

Fundic gland polyp

Cystically dilated oxyntic glands

Typically no or minimal inflammation

Inflammatory/hyperplastic polyp

Edematous lamina propria

Variable acute and chronic inflammation

Slide 36 · Low-power recognition: Gland dilation beneath mucosa

Schematic — not a histologic specimen

Seek expanded glandular spaces within a polypoid mucosal fragment.

Confirm that the lesion is composed of glands rather than a solid cell proliferation.

This is an original schematic, not a patient photomicrograph.

Slide 37 · Higher-power recognition: Epithelial composition

Schematic — not a histologic specimen

Inspect the actual gland lining for oxyntic components.

Parietal, chief and foveolar cells form the described epithelial mixture.

Document any atypical architecture or nuclear changes rather than assuming blandity.

Slide 38 · Recognition depends on convergent findings

Body / fundus

Smooth localized polyp

Cystically dilated irregular glands

Oxyntic + foveolar lining

Minimal inflammation strengthens the classic pattern.

Slide 39 · The major histologic rival is a hyperplastic polyp

Fundic gland polyp

Cystically dilated irregular glands

Parietal and chief cells among lining

Hyperplastic polyp

Elongated, irregular foveolar glands

Edematous inflamed lamina propria

Slide 40 · Hyperplastic polyps emphasize foveolar architecture

Schematic — not a histologic specimen

Irregular, cystically dilated and elongated foveolar glands.

Corkscrew-shaped foveolar structures may be prominent.

Cystic gland change alone is not specific for fundic gland polyps.

Slide 41 · Inflamed stroma helps separate the patterns

Feature

Fundic gland polyp

Inflammatory / hyperplastic

Inflammation

Absent or minimal

Variable acute and chronic

Lamina propria

No defining edema stated

Typically edematous

Gland lineage

Oxyntic + foveolar

Predominantly foveolar

Slide 42 · Gastric adenoma is a neoplastic comparator

A gastric adenoma is distinguished by a dysplastic epithelial phenotype.

Robbins commonly places gastric adenomas in a background of atrophy and intestinal metaplasia.

Unlike classic fundic gland polyps, adenoma classification fundamentally depends on epithelial dysplasia.

Slide 43 · Adenoma features include nuclear alteration

Adenoma

Epithelial nuclear hyperchromasia

Nuclear pseudostratification

Dysplastic epithelial growth

Fundic gland polyp

Cystically dilated glands

Parietal / chief / foveolar lining

Dysplasia risk depends on setting

Slide 44 · Core differential: Three diagnostic patterns

Feature

Fundic gland

Hyperplastic

Adenoma

Dominant change

Oxyntic gland cysts

Foveolar elongation

Epithelial dysplasia

Inflammation

Usually scant

Often conspicuous

Variable

Key interpretation

Context-dependent risk

Reactive/inflammatory

Neoplastic lesion

Slide 45 · The word “cystic” is not itself a diagnosis

Both fundic gland polyps and hyperplastic polyps may have cystic gland dilatation.

The discriminators are glandular cell composition, foveolar elongation, and stromal inflammation.

Classification requires the entire architecture and cytology, not one isolated feature.

Interpretation

Architecture + cell lineage + inflammation > cysts alone.

Slide 46 · Antral gland and body gland origins differ

Fundus

Body

Antrum

Regional schematic

Body/fundus are the main oxyntic compartment and typical fundic gland polyp site.

Antrum contains gastrin-secreting G cells and differs in gland composition.

The regional map explains both morphology and the PPI feedback pathway.

Slide 47 · A reproducible morphology-reading sequence

Localize the mucosa

Read gland shape

Identify lining cells

Assess inflammation

Search for dysplasia

Teaching synthesis of source findings, not a formal society-endorsed algorithm.

Slide 48 · Dysplasia requires a contextual interpretation

When FAP is present

Dysplasia may occur in FAP-associated fundic gland polyps.

Rare cancers have been reported in this setting.

When lesions are sporadic

No significant neoplastic risk.

This statement includes PPI-associated sporadic polyps.

Slide 49 · FAP-associated polyps can show dysplasia

Dysplasia may occur

Do not extrapolate to every fundic gland polyp

FAP is linked to germline APC mutation.

The source flags dysplasia specifically in the FAP-associated setting.

Slide 50 · Rare cancers have been reported in FAP

Rare cancers reported

Not equivalent to a quantified transformation rate

Rare cancers associated with FAP-associated fundic gland polyps.

No numerical frequency or staging algorithm is supplied in the excerpt.

Slide 51 · Sporadic fundic gland polyps have a different risk

No significant neoplastic risk

As characterized by Robbins, 11th edition

The sporadic category contrasts with FAP-associated lesions.

Do not transfer inherited risk to a sporadic diagnosis without evidence.

Slide 52 · PPI-associated lesions share the sporadic risk statement

No significant neoplastic risk

Includes sporadic polyps arising with PPI therapy

PPI exposure is linked to the rise in sporadic fundic gland polyps.

The excerpt distinguishes this association from familial dysplasia risk.

Slide 53 · Risk stratification depends on disease context

Clinical setting

What Robbins supports

Sporadic fundic gland polyp

No significant neoplastic risk

PPI-associated sporadic polyp

No significant neoplastic risk

FAP-associated fundic gland polyp

Dysplasia may occur; Rare cancers reported

MUTYH-associated setting

Association established; Specific dysplasia rate not provided

Slide 54 · Symptoms are often absent

Fundic gland polyps may be completely asymptomatic.

The endoscopic detection of a polyp does not mean it caused the presenting complaint.

Histologic classification should remain separate from symptom attribution.

Interpretation

Asymptomatic is explicitly within the clinical spectrum.

Slide 55 · Symptomatic patients can have nonspecific complaints

Nausea is a reported associated symptom.

Vomiting and epigastric pain are also reported.

These complaints do not distinguish a fundic gland polyp from other gastric disorders on their own.

Slide 56 · Clinical reasoning needs both context and tissue

Endoscopic observation

Body/fundus gland morphology

Drug / hereditary context

Risk-aware interpretation

This framework derives from the source; It is not a procedural management guideline.

Slide 57 · Case A — multiple polyps during PPI therapy

Teaching vignette: Endoscopy identifies several smooth body/fundus polyps in an individual taking a proton pump inhibitor. Biopsy shows cystically dilated oxyntic glands with little inflammation.

Which association and risk statement are most consistent with Robbins?

Suggested interpretation

PPI-associated sporadic fundic gland polyps; No significant neoplastic risk assigned.

Slide 58 · Case B — fundic gland polyp in FAP

Teaching vignette: A patient with familial adenomatous polyposis has a fundic gland polyp. A biopsy shows epithelial dysplasia.

Why does this result require a different interpretation from Case A?

Suggested interpretation

Robbins specifically describes dysplasia in FAP-associated fundic gland polyps and rare reported cancers.

Slide 59 · Case C — cystically dilated foveolar glands

Teaching vignette: A gastric polyp has elongated irregular foveolar glands, edematous lamina propria, and a prominent inflammatory infiltrate.

What diagnosis is better supported than a classic fundic gland polyp?

Suggested interpretation

An inflammatory / hyperplastic gastric polyp.

Slide 60 · Case D — hyperchromasia and pseudostratification

Teaching vignette: A gastric polyp is composed of dysplastic epithelium with nuclear hyperchromasia and pseudostratification.

Which comparator should be considered?

Suggested interpretation

Gastric adenoma, rather than an uncomplicated fundic gland polyp.

Slide 61 · A five-step clinicopathologic checklist

Confirm gastric body/fundus location where documented.

Recognize cystically dilated irregular gland architecture.

Identify parietal, chief and foveolar lining components.

Assess inflammation and actively evaluate epithelial atypia.

Incorporate PPI use, APC/FAP or MUTYH-associated context.

Interpretation

The checklist integrates supplied textbook findings; Not a formal guideline.

Slide 62 · Summary: The defining discriminators

Dimension

Fundic gland polyp

Site

Body and fundus

Gross

Smooth; Well circumscribed; Single or multiple

Microscopy

Irregular cystic glands; Parietal, chief, foveolar cells

Inflammation

Typically absent or minimal

Clinical association

Sporadic, PPI exposure, APC/FAP, MUTYH

Risk

Sporadic low; FAP-linked dysplasia possible

Slide 63 · Selected source and visual references

Robbins, Cotran & Kumar. Pathologic Basis of Disease, 11th ed. (2026). Chapter 17, pp. 696, 704–705.

Robbins Figure 17.19 caption: fundic gland polyp with cystically dilated glands lined by parietal, chief, and foveolar cells.

Original editable schematics in this lecture; no textbook micrographs or third-party histologic images reproduced.