Zollinger Ellison Syndrome

Slide 1 · Zollinger–Ellison syndrome

Gastrinoma, gastric hypersecretion, and peptic ulcer disease

Gastrin • Oxyntic hyperplasia • Peptic injury

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

Connect gastrinoma-derived gastrin to gastric epithelial growth and acid injury.

Recognize the characteristic oxyntic mucosal response and ulcer distribution.

Distinguish sporadic gastrinomas from MEN1-associated disease.

Link gastric acid control, tumor localization, and neoplasm-directed management.

Slide 3 · One endocrine lesion, two tissue-level consequences

Gastrinoma

Gastrin-secreting neuroendocrine tumor

Hypergastrinemia

Sustained hormone-driven gastric stimulation

Gastric response

Oxyntic gland hyperplasia and acid hypersecretion

Clinical effects

Peptic ulceration ± chronic diarrhea

Zollinger–Ellison syndrome is a functional neoplastic endocrine syndrome.

Slide 4 · The syndrome is not a primary gastric neoplasm

Source lesion

Gastrinoma in small intestine, pancreas, or adjacent soft tissue.

Target organ

Oxyntic mucosa of the gastric body and fundus.

Clinical injury

Acid-related lesions in duodenum, stomach, or even jejunum.

Slide 5 · Gastrinomas are neuroendocrine neoplasms

The defining secretory product is gastrin.

A functional tumor can cause major physiological disturbance without bulky local growth.

An endocrine tumor and its downstream mucosal effects must be assessed separately.

The gastric changes are a hormone-induced response, not a primary gastric gastrinoma.

Slide 6 · Gastrinoma location: Bowel and pancreas

Duodenum / small bowel

An important primary site; Particularly characteristic in MEN1.

Pancreas

Typical location of many solitary sporadic tumors.

Peripancreatic region

The endocrine chapter includes soft tissues around the pancreas within the recognized gastrinoma region.

Slide 7 · The “gastrinoma triangle” is a clinical region

Small bowel

Duodenal primary gastrinoma.

Peripancreatic tissues

Extra-pancreatic sites in the regional soft tissues.

Pancreas

Pancreatic primary gastrinoma.

Site categories are schematic; No anatomic scale or spatial boundaries are implied.

Slide 8 · Location and secretory phenotype answer different questions

Question

What it establishes

What it does not establish

Where is the lesion?

Anatomic origin and potential resectability

Whether acid hypersecretion is controlled

What does it secrete?

Gastrin-dependent syndrome

Tumor burden or metastatic extent

How has it spread?

Neoplastic dissemination

Degree of current gastric acid injury

Slide 9 · Gastrin links endocrine and gastrointestinal pathology

Gastrin excess

Tumor-derived hormone

Oxyntic trophic effect

Expansion of multiple gastric gland cell populations

Acid secretory effect

Gastric hypersecretion and increased peptic injury

Two parallel downstream effects of excess gastrin.

Slide 10 · The oxyntic mucosa is the central target

Anatomic distribution

Predominantly gastric fundus and body.

Baseline function

Acid-producing parietal-cell compartment.

ZES alteration

Markedly increased mucosal thickness and gland-cell populations.

Slide 11 · Gastric thickening reflects gland-cell hyperplasia

Persistent hypergastrinemia

Sustained trophic stimulus

Cell proliferation

Parietal, mucous neck and endocrine cells

Thicker oxyntic mucosa

Gastric hypertrophic gastropathy phenotype

“Hypertrophic” describes the macroscopic effect; The microscopic process is hyperplasia.

Slide 12 · Parietal cell hyperplasia dominates the response

Massive parietal-cell hyperplasia is the striking microscopic feature.

Parietal cells populate the oxyntic mucosa of body and fundus.

Increased secretory-cell mass accompanies acid hypersecretion.

Thicker oxyntic mucosa provides a morphologic clue to a circulating stimulus.

Slide 13 · Mucous neck cells also expand

Gastrin promotes mucous neck cell hyperplasia.

Expansion is part of a broader oxyntic gland response, not an isolated surface lesion.

Cellular composition distinguishes Zollinger–Ellison syndrome from foveolar-predominant disorders.

The phenotype is mixed glandular hyperplasia, despite parietal-cell predominance.

Slide 14 · Endocrine cell hyperplasia accompanies the gland response

Oxyntic endocrine cells also increase under the influence of gastrin.

This component helps explain why multiple cell populations expand together.

Gastric neuroendocrine cell hyperplasia may occur in several other settings.

Context and acid physiology are necessary to interpret endocrine cell expansion.

Slide 15 · Three cellular compartments respond to gastrin

Parietal cells

Massive hyperplasia: The defining tissue change.

Mucous neck cells

Additional hyperplasia within gastric glands.

Endocrine cells

Associated oxyntic neuroendocrine hyperplasia.

Slide 16 · The stomach displays a hormone-driven phenotype

Hormone excess

Circulating gastrin

Cellular response

Multilineage oxyntic hyperplasia

Tissue response

Thickened fundic/body mucosa

Functional response

Excess acid secretion

Morphology and physiology should be interpreted together.

Slide 17 · ZES belongs among hypertrophic gastropathies

Hypertrophic gastropathies produce enlarged gastric rugal folds through epithelial hyperplasia.

They can show a conspicuous, cerebriform macroscopic appearance.

The key differential is the hyperplastic epithelial cell population.

Ménétrier disease and Zollinger–Ellison syndrome exemplify distinct growth stimuli.

Slide 18 · Enlarged folds are a pattern, not a diagnosis

Gross observation

Large gastric folds indicate expanded mucosal tissue.

Microscopic assignment

Identify parietal, mucous, and endocrine compartments.

Physiological interpretation

Ask whether acid is increased or reduced.

Slide 19 · ZES versus Ménétrier disease: Cellular target

Feature

Zollinger–Ellison syndrome

Ménétrier disease

Primary stimulus

Gastrin excess

TGF-α → EGFR activation

Predominant mucosal response

Parietal cells; also neck and endocrine cells

Foveolar mucous-cell hyperplasia

Oxyntic cell status

Marked parietal hyperplasia

Parietal/chief cell hypoplasia may accompany foveolar growth

Slide 20 · ZES versus Ménétrier disease: Clinical signature

Feature

Zollinger–Ellison syndrome

Ménétrier disease

Characteristic syndrome

Severe acid-related peptic injury

Protein-losing gastropathy

Prominent complications

Ulceration and possible perforation

Hypoproteinemia, edema and weight loss

Association in Robbins table

MEN1; no gastric dysplasia association noted

Increased gastric adenocarcinoma risk in adults

Slide 21 · Why protein loss points away from classic ZES

Ménétrier disease

Foveolar cell growth

Abnormal mucosal barrier

Albumin leakage

Systemic effect

Hypoproteinemia and peripheral edema

A contrasting mechanism; It should not be substituted for gastrin-driven acid disease.

Slide 22 · Oxyntic hyperplasia versus oxyntic atrophy

Feature

ZES

Autoimmune atrophic gastritis

Oxyntic mucosa

Thickened / hyperplastic

Atrophic / thinned

Parietal cells

Markedly increased

Depleted

Acid physiology

Hypersecretion

Decreased secretion

Elevated gastrin

Hormone produced by tumor

Compensatory response may occur with hypochlorhydria

Slide 23 · High gastrin alone does not define one pathology

In Zollinger–Ellison syndrome, gastrin originates from a gastrinoma.

Autoimmune atrophic gastritis can show markedly increased gastrin despite reduced acid.

The state of oxyntic glands discriminates these mechanisms.

Interpret hormone measurements in their morphological and functional context.

Slide 24 · Gastrinoma-associated ulcers versus common PUD

Feature

ZES-associated ulceration

Common peptic ulcer disease

Dominant driver

Gastrinoma-associated acid hypersecretion

Usually H. pylori, NSAIDs or smoking

Distribution

Stomach, duodenum; may include jejunum

Predominantly proximal duodenum or stomach

Multiplicity

May be multiple and persistent

More than 80% solitary in textbook PUD series

Diagnostic inference

Consider an endocrine source

Search for usual mucosal injurious factors

Slide 25 · Peptic ulceration reflects defense–injury imbalance

Protective defenses

Mucus, epithelial repair and local mucosal blood flow counter acid injury.

Damaging factors

Gastric acid and peptic injury rise with gastrin-driven hypersecretion.

A relative excess of damaging activity favors chronic ulceration.

Slide 26 · Why gastrinoma produces severe peptic injury

Functional neoplasm

Gastrin release

Gastric acid hypersecretion

Persistently elevated damaging factor

Peptic mucosal injury

Ulcer development and impaired resolution

The neoplasm need not be gastric to injure the stomach or intestine.

Slide 27 · Duodenal ulcers are a common presenting lesion

Patients with Zollinger–Ellison syndrome often present with duodenal ulcers.

The proximal duodenum is a frequent site of peptic injury generally.

Ulcer identification is a manifestation of the syndrome, not a localization of gastrinoma.

Multiple or treatment-resistant lesions strengthen suspicion of excess acid.

Slide 28 · Jejunal ulcers are an unusually strong clue

Typical peptic disease

Duodenum and stomach are the predominant sites.

ZES-associated extension

Ulcers can appear at more distal sites, including jejunum.

Clinical inference

Intractable jejunal ulceration is emphasized as a reason to suspect ZES.

Slide 29 · Multiplicity changes the interpretation of ulcer disease

Usual peptic ulcer disease is solitary in more than four-fifths of patients.

Gastrinoma-associated gastric and duodenal ulcers can be multiple.

Morphology of any single ulcer may resemble ordinary peptic ulcer disease.

Pattern and distribution carry additional diagnostic information.

Slide 30 · Peptic ulcers have characteristic gross geometry

Surface defect

Round-to-oval, sharply punched-out mucosal lesion.

Edges

Often relatively level with adjacent mucosa; May overhang.

Important distinction

Heaped-up margins are more concerning for malignancy.

Slide 31 · Histologic ulcer architecture is not ZES-specific

Luminal surface

Fibrinoid debris and neutrophils.

Reparative zone

Granulation tissue and immature vessels.

Deep chronic zone

Fibrous scar and altered vessels.

Layer descriptions are conceptual; Not an observed photomicrograph.

Slide 32 · Ulcer bleeding arises from deep vessel injury

Ulcer penetrates

Loss of protective mucosal layers

Vascular involvement

Vessels in granulation tissue or scar may erode

Clinical result

Hemorrhage or iron deficiency anemia

Major hemorrhage can be the first manifestation of peptic ulcer disease.

Slide 33 · Perforation is an acid-injury emergency

Persistent ulceration

Deepening tissue destruction

Wall penetration

Full-thickness defect

Peritoneal contamination

Acute surgical emergency

Acid suppression as a means of preventing gastric perforation in ZES.

Slide 34 · Chronic ulceration may produce obstruction

Obstruction is a recognized complication of peptic ulcer disease.

Edema and long-standing scar formation may narrow the outflow pathway.

Pyloric channel ulcers are a typical setting; Duodenal ulcers may also obstruct.

Crampy pain and intractable vomiting may indicate severe narrowing.

Slide 35 · Ulcer complications can dominate clinical care

Complication

Structural lesion

Clinical consequence

Bleeding

Deep vascular erosion

Anemia or life-threatening hemorrhage

Perforation

Transmural ulcer defect

Peritonitis and emergency surgery

Obstruction

Edema or cicatricial narrowing

Persistent vomiting and impaired gastric emptying

Slide 36 · Chronic diarrhea is part of the syndrome

Chronic diarrhea is a common presenting feature of Zollinger–Ellison syndrome.

Diarrhea may coexist with duodenal ulceration or predominate clinically.

The combination of diarrhea and severe peptic disease should raise the diagnostic possibility.

A diarrhea-only presentation should not be equated automatically with infectious enteritis.

Slide 37 · Clinical suspicion comes from a pattern

Recurrent ulceration

Severe, multiple or otherwise difficult peptic ulcers.

Unusual distribution

Jejunal involvement beyond typical proximal sites.

Syndrome association

Chronic diarrhea or signs of another endocrine lesion.

Slide 38 · Ulcers may look ordinary despite an unusual cause

The endocrine chapter describes gastrinoma-associated ulcers as histologically identical to common peptic ulcers.

What changes is the distribution, number, persistence and causal mechanism.

Pathology should be integrated with clinical endoscopy and endocrine evaluation.

Microscopy of an ulcer cannot, by itself, identify a gastrinoma.

Slide 39 · Most gastrinomas are sporadic in the chapter 17 series

Sporadic disease

Approximately 75% of gastrinomas. Usually solitary.

MEN1-associated disease

Approximately 25%; Often younger patients with multiple lesions.

Textbook proportions; These are descriptive, not patient-level probabilities.

Slide 40 · Sporadic gastrinomas often present as solitary lesions

The chapter 17 description emphasizes a single tumor in sporadic disease.

The pancreas is a characteristic site for sporadic lesions.

Gastrin-secreting endocrine neoplasms can nonetheless be invasive or metastatic.

An isolated lesion should not be assumed biologically benign from appearance alone.

Slide 41 · MEN1-associated gastrinomas are often multiple

Typical patient context

Younger individual with hereditary endocrine neoplasia.

Anatomic pattern

Multiple small duodenal tumors are common.

Behavioral concern

Metastatic disease may occur even with small primary lesions.

Slide 42 · MEN1 makes multiplicity a diagnostic clue

MEN1 predisposition

Inherited endocrine tumor syndrome

Multifocal origin

Several duodenal / pancreatic endocrine lesions

Clinical problem

Localization and durable tumor control become more complex

Do not assume a single dominant lesion accounts for all endocrine pathology.

Slide 43 · MEN1 is caused by alterations of a tumor suppressor

MEN1 syndrome results from germline pathogenic changes in the MEN1 tumor-suppressor gene.

MEN1 encodes menin, a component of transcription-regulatory complexes.

Its context-dependent partners can promote or restrict tumorigenesis.

In sporadic gastrinomas, somatic MEN1 abnormalities also have biologic relevance.

Slide 44 · MEN1: The three endocrine “P” organs

Parathyroid

Primary hyperparathyroidism; Often the earliest manifestation.

Pancreas / enteropancreatic system

Functioning neuroendocrine tumors, including gastrinomas and insulinomas.

Pituitary

Often prolactinoma; Other secretory tumors can occur.

Slide 45 · Parathyroid clues can unmask MEN1

Primary hyperparathyroidism is the most frequent MEN1 manifestation.

Parathyroid lesions may be hyperplastic or adenomatous.

PTH-associated hypercalcemia can manifest as nephrolithiasis.

In a patient with ZES, a history of renal stones should prompt endocrine syndromic consideration.

Slide 46 · Enteropancreatic MEN1 disease is often multifocal

Tumors may arise simultaneously or at separate times.

Numerous pancreatic microadenomas can coexist with dominant lesions.

Duodenal gastrinomas are particularly important in MEN1.

Functioning tumors cause distinct hormone-hypersecretion syndromes.

Slide 47 · Pituitary disease extends the differential

Prolactinomas are common pituitary lesions in MEN1.

Somatotropin-producing tumors and acromegaly may occur.

A multi-gland presentation points away from an isolated sporadic gastrinoma.

The clinical history should identify both functioning and nonfunctioning endocrine tumors.

Slide 48 · The endocrine syndrome can explain disparate symptoms

Gastrinoma

Intractable ulcers with or without diarrhea.

Parathyroid tumor

Hypercalcemia and nephrolithiasis.

Pituitary tumor

Clinical manifestations of prolactin excess.

Parallel manifestations of a common inherited predisposition; Not a causal sequence.

Slide 49 · Gastrinoma cytology may look deceptively bland

Gastrin-secreting tumors as often histologically bland.

Gross or microscopic anaplasia need not be conspicuous.

A bland endocrine tumor can be locally invasive or metastatic.

Behavior cannot be inferred safely from atypia alone.

Slide 50 · Neuroendocrine grade and stage are not synonyms

Attribute

Represents

Teaching caution

Differentiation / proliferation

Cellular phenotype and growth rate

Does not replace assessment of spread

Local invasion

Extension beyond site of origin

May occur in bland-appearing tumor

Metastasis

Documented neoplastic dissemination

A decisive adverse biologic feature

Slide 51 · Metastatic disease shapes long-term prognosis

The endocrine chapter describes more than half of gastrinomas as locally invasive or metastatic when diagnosed.

The presence of hepatic metastases signals an adverse prognosis.

Long-term outcome depends strongly on the underlying neoplasm, not simply ulcer control.

Acid suppression treats the syndrome but does not itself remove metastatic tumor.

Slide 52 · MEN1 mutations matter beyond inherited disease

Somatic MEN1 mutations can be identified in some sporadic neuroendocrine tumors.

MEN1-mutated sporadic gastrinomas with more frequent metastasis.

This observation is about tumor biology, not a validated standalone individual prognostic threshold.

Tumor genotyping and germline MEN1 syndrome should not be conflated.

Slide 53 · Tumor localization is distinct from syndrome recognition

Suspected gastrinoma

Clinical endocrine syndrome

Anatomic localization

Define pancreatic, bowel or peripancreatic site

Disease assessment

Consider multiplicity and spread

Treatment planning

Determine feasibility of directed treatment

A positive ulcer finding does not reveal the tumor location.

Slide 54 · Endoscopic ultrasonography can localize tumors

Modality

Endoscopic ultrasonography (EUS).

Clinical role

High-resolution assessment of suspected lesions near the gastrointestinal tract.

Interpretation limit

Localization imaging does not itself measure the physiological impact of gastrin.

Slide 55 · Somatostatin receptor imaging exploits tumor biology

Modality

Somatostatin receptor scintigraphy, as.

Rationale

Tumor localization using neuroendocrine receptor expression.

Interpretation limit

Imaging complements rather than substitutes for endocrine and anatomic evaluation.

Slide 56 · Tumor distribution changes localization strategy

Clinical setting

Expected tumor pattern

Implication

Sporadic gastrinoma

Often one pancreatic lesion

Search for a focal primary and spread

MEN1-associated ZES

Often multiple duodenal tumors

Evaluate multiplicity, not only the dominant mass

Disseminated disease

Metastatic deposits may occur

Stage burden in addition to identifying the origin

Slide 57 · Management has two simultaneous targets

Physiological control

Suppress excessive gastric acid to heal ulcers and prevent injury.

Neoplasm-directed care

Treat or remove the underlying gastrinoma to address the source.

Parallel management objectives: Symptom control is not tumor eradication.

Slide 58 · Proton pump inhibitors are first-line acid control

Proton pump inhibitors suppress gastric acid hypersecretion in ZES.

Effective acid suppression permits ulcer healing.

Controlling acid injury reduces the danger of gastric perforation.

Acid blockade stabilizes the patient while the gastrinoma is evaluated and treated.

Slide 59 · Ulcer healing does not establish tumor cure

Measured outcome

Primarily reflects

Cannot establish alone

Pain/ulcer improvement

Successful acid suppression

Gastrinoma eradication

Endoscopic healing

Repair of gastric/duodenal injury

Absence of metastasis

Definitive tumor treatment

Neoplasm-directed management

Automatic reversal of every associated endocrine condition

Slide 60 · Resectability influences tumor-directed management

When feasible, complete removal of the gastrinoma can eliminate the hormonal syndrome.

Multifocal disease in MEN1 complicates complete tumor clearance.

Extent and location of metastases influence long-term management.

Acid suppression continues to address immediate peptic risk when tumor eradication is not possible.

Slide 61 · Metastatic disease may benefit from somatostatin analogues

Somatostatin analogues as potentially beneficial in metastatic gastrinoma.

The neoplasm remains the central determinant of long-term survival.

This treatment concept is distinct from proton pump inhibition of gastric acid.

Specific contemporary drug regimens and response rates are not detailed in the supplied section.

Slide 62 · Why both treatment goals must be reassessed

Suppress acid

Prevent further ulcer injury

Monitor tumor burden

Identify progression or spread

Reconcile both outcomes

Clinical control does not imply oncologic control

A patient can have healed ulcers and still harbor progressive neuroendocrine disease.

Slide 63 · Case: Recurrent ulcers with diarrhea

Clinical scenario

An adult has repeated duodenal peptic ulcers despite treatment and also reports chronic diarrhea. No discrete gastric mass is identified.

Discussion prompts

What syndrome unifies the presentation?

Which organ contains the likely secretory source?

Which gastric cell population would be increased?

Slide 64 · Case analysis: Mechanism precedes location

Syndrome

Zollinger–Ellison syndrome should enter the differential.

Source

A gastrin-producing neuroendocrine lesion of bowel or pancreas.

Expected stomach

Marked parietal-cell hyperplasia with thicker oxyntic mucosa.

Slide 65 · Case: Jejunal ulcer with renal stones

Clinical scenario

A younger patient has intractable jejunal ulceration and a history of recurrent nephrolithiasis.

Discussion prompts

Which inherited endocrine syndrome should be considered?

What other endocrine organs are commonly involved?

Would multifocal or solitary gastrinoma be more characteristic?

Slide 66 · Case analysis: Screen for an endocrine syndrome

Unifying predisposition

MEN1 is consistent with ZES plus potential parathyroid disease.

Further endocrine context

Parathyroid, enteropancreatic tissues and pituitary.

Gastrinoma pattern

Multiple small duodenal lesions are characteristic of MEN1.

Slide 67 · Pattern recognition: Four different gastric settings

Setting

Dominant tissue process

Useful discriminant

Zollinger–Ellison

Parietal/neck/endocrine hyperplasia

Acid hypersecretion and unusual peptic ulcers

Ménétrier

Foveolar hyperplasia with oxyntic hypoplasia

Protein loss and edema

Autoimmune atrophic gastritis

Destruction of oxyntic glands

Low acid despite high gastrin

Common PUD

Ulceration without required global oxyntic hyperplasia

Usual H. pylori / NSAID / smoking context

Slide 68 · From pathological observation to causal inference

Unusual / multiple ulcers

Recognize the clinical phenotype

Thickened oxyntic mucosa

Identify gastrin-responsive gastric changes

Gastrinoma

Locate the endocrine source

MEN1 assessment

Ask whether disease is multifocal/heritable

The explanatory diagnosis connects three anatomic sites: Tumor, stomach and injured gut.

Slide 69 · Core pathological synthesis

Causal lesion

Gastrin-secreting neuroendocrine tumor.

Signature morphology

Marked oxyntic parietal-cell hyperplasia, with neck/endocrine growth.

Clinical signature

Acid-related peptic ulceration, sometimes distal, plus chronic diarrhea.

Natural history

MEN1 status, multiplicity and metastasis modify prognosis.

Slide 70 · Practical clinical synthesis

Recognize the endocrine cause when ulcer distribution, multiplicity or course is atypical.

Distinguish the source tumor from its hormone-driven gastric response.

Use tumor localization and MEN1 context to frame disease extent.

Suppress acid promptly, while continuing neoplasm-directed evaluation.

Slide 71 · Source references

Robbins, Cotran & Kumar. Pathologic Basis of Disease. 11th ed. 2026. Chapter 17: The Gastrointestinal Tract, pp. 699–704.

Robbins, Cotran & Kumar. Pathologic Basis of Disease. 11th ed. 2026. Chapter 24: The Endocrine System, pp. 1011–1012 and 1025–1026.

Figures are original editable schematics or tables derived from supplied text; no photomicrographs are reproduced.