Pancreas Divisum

Slide 1 · Pancreas divisum

SEPARATE DUCT SYSTEMS

Dorsal-derived gland

body • tail • upper head

Ventral-derived gland

lower / posterior head

Minor papilla

Major papilla

no communicating duct

Schematic: exocrine ductal pathways, not to scale

Congenital pancreatic ductal variant due to failed duct fusion.

Most exocrine pancreatic drainage reaches the minor papilla.

Clinical importance lies in the minority with pancreatitis.

Schematic: dorsal and ventral pancreatic duct drainage.

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning outcomes: Anatomy to clinical reasoning

Development

Duct anatomy

Clinical inference

Conceptual sequence

Trace dorsal and ventral pancreatic contributions to the adult gland.

Compare pancreatic outflow in normal fusion and divisum.

Interpret pancreatitis risk and the limitations of intervention evidence.

Slide 3 · A ductal variant, not an inflammatory diagnosis

Congenital duct pattern

Anatomical finding

Acute pancreatitis

Inflammatory episode

Chronic pancreatitis

Irreversible parenchymal injury

Divisum describes how ducts are connected and where they drain.

Pancreatitis describes pancreatic injury, not a ductal phenotype.

The two can coexist without a proven causal relationship in every case.

Slide 4 · Pancreas divisum is the commonest congenital variant

3–10%

Frequency reported by Robbins (11th ed.)

Robbins characterizes divisum as the most common congenital pancreatic anomaly.

Reported frequency reflects a congenital anatomic pattern.

Prevalence is not the same as the risk of symptomatic disease.

Slide 5 · Why pancreatic duct anatomy matters

Acinar secretion

Ductal transport

Duodenal lumen

Conceptual sequence

Most pancreatic tissue is exocrine and makes digestive zymogens.

Ductules and ducts carry secretions toward the duodenum.

The final drainage route can matter when papillary outflow is limited.

Slide 6 · Dorsal and ventral pancreatic primordia

Separate buds

Dorsal | Ventral

Rotation / approximation

Adjacent primordia

Ductal fusion

Communicating ducts

Conceptual sequence · not anatomical scale

The pancreas arises from two foregut outpouchings.

The primordia normally merge as the pancreas develops.

Their duct systems usually establish a communicating pathway.

Slide 7 · The developmental fusion window

Separate buds

Dorsal | Ventral

Rotation / approximation

Adjacent primordia

Ductal fusion

Communicating ducts

Conceptual sequence · not anatomical scale

Fusion between gestational weeks 5 and 8.

This process involves coordinated rotation and approximation.

Imperfection in development produces congenital ductal variants.

Slide 8 · Dorsal primordium: Most of the gland

Body

Dorsal primordium

Tail

Dorsal primordium

Superior / anterior head

Dorsal primordium

The dorsal primordium forms the body and tail of the pancreas.

It also contributes the superior/anterior portion of the head.

Its large parenchymal contribution explains dominant dorsal drainage in divisum.

Slide 9 · Ventral primordium: A smaller region

Posterior head

Ventral origin

Inferior head

Ventral origin

Ductal endpoint

Major papilla

The ventral primordium forms posterior/inferior pancreatic head.

The ventral drainage pathway connects with the major papilla.

In divisum, this route drains a relatively small portion of the gland.

Slide 10 · Normal development produces ductal communication

Separate buds

Dorsal | Ventral

Rotation / approximation

Adjacent primordia

Ductal fusion

Communicating ducts

Conceptual sequence · not anatomical scale

The two pancreatic primordia become anatomically united.

Ductal fusion creates communication between their networks.

Dominant exocrine outflow is ordinarily via the major papilla.

Slide 11 · Pancreas divisum: Failure of ductal fusion

Separate buds

Dorsal | Ventral

Rotation / approximation

Adjacent primordia

Ductal nonfusion

Two drainage routes

Conceptual sequence · not anatomical scale

The fetal dorsal and ventral duct systems fail to fuse.

A dominant dorsal drainage route persists toward the minor papilla.

Ventral drainage remains separate toward the major papilla.

Slide 12 · Distinguish failure of fusion from failed organ growth

Divisum

Nonfused ducts

Annular pancreas

Ventral rotation anomaly

Agenesis

Failed development of gland

Pancreas divisum concerns the exocrine ductal connections.

An annular pancreas is a different congenital developmental problem.

Pancreatic agenesis is not interchangeable with ductal divisum.

Slide 13 · The duct of Wirsung

NORMAL DUCT FUSION

Dorsal-derived gland

Body • tail • upper head

Ventral-derived gland

Lower / posterior head

Minor papilla

Major papilla

Dominant fused route

Wirsung is the main pancreatic duct in normal fused anatomy.

It joins the common bile duct near the major papilla of Vater.

In divisum, its ventral component drains only a small head region.

Slide 14 · The duct of Santorini

SEPARATE DUCT SYSTEMS

Dorsal-derived gland

Body • tail • upper head

Ventral-derived gland

Lower / posterior head

Minor papilla

Major papilla

No communicating duct

Santorini is conventionally the accessory pancreatic duct.

It reaches the duodenum through the minor papilla.

In divisum it is the dominant pathway for most pancreatic secretions.

Slide 15 · Two duodenal papillae, different outflow routes

Minor papilla

Dorsal drainage in divisum

Major papilla

Bile + ventral drainage

Key distinction

Separate duct outlets

The major papilla of Vater also receives the common bile duct.

The minor papilla is the terminal outlet of the dorsal duct.

In divisum, these two routes do not unite upstream.

Slide 16 · Normal drainage: The fused configuration

NORMAL DUCT FUSION

Dorsal-derived gland

Body • tail • upper head

Ventral-derived gland

Lower / posterior head

Minor papilla

Major papilla

Dominant fused route

Main pancreatic duct drains predominantly via the major papilla.

The accessory duct can drain through the minor papilla.

Communicating ducts distinguish this from complete divisum.

Slide 17 · Divisum drainage: The unfused configuration

SEPARATE DUCT SYSTEMS

Dorsal-derived gland

Body • tail • upper head

Ventral-derived gland

Lower / posterior head

Minor papilla

Major papilla

No communicating duct

Most tissue drains via Santorini and the minor papilla.

The ventral duct of Wirsung drains a small part of the head.

The ducts lack the usual major communication.

Slide 18 · The dominant drainage route is reversed

Normal

Predominant → major papilla

Divisum

Predominant → minor papilla

Clinical question

Can minor outflow keep pace?

The anatomical landmark is the papilla receiving bulk secretion.

Major papilla predominance describes typical fused anatomy.

Minor papilla predominance defines the functional drainage concern in divisum.

Slide 19 · Why the small-caliber minor papilla is relevant

Large dorsal bed

Minor papilla

Potential resistance

Conceptual sequence

The minor papilla as a small-caliber outlet.

The dorsal primordium supplies most exocrine parenchyma.

Relatively high flow through a narrow outlet motivates an outflow hypothesis.

Slide 20 · The essential normal-versus-divisum comparison

Duct fusion

Present | absent

Bulk drainage

Major | minor

Ventral territory

Part of fused pathway | small head area

Anatomical fusion—not pancreatic size—is the defining difference.

The terminal papilla of dominant drainage changes.

Both patterns can coexist with otherwise intact pancreatic tissue.

Slide 21 · Complete divisum: No ductal communication

SEPARATE DUCT SYSTEMS

Dorsal-derived gland

Body • tail • upper head

Ventral-derived gland

Lower / posterior head

Minor papilla

Major papilla

No communicating duct

Complete divisum means the dorsal and ventral ducts remain separate.

The dorsal duct reaches the minor papilla independently.

A small ventral duct empties through the major papilla.

Slide 22 · Incomplete divisum: A residual communication

INCOMPLETE DUCT FUSION

Dorsal-derived gland

Body • tail • upper head

Ventral-derived gland

Lower / posterior head

Minor papilla

Major papilla

Tiny duct connection

Incomplete divisum retains a small duct connecting both systems.

Despite this connection, dorsal-to-minor drainage may predominate.

The distinction requires careful visualization of the tiny connecting duct.

Slide 23 · Ductal phenotype must be described precisely

Complete

No dorsal–ventral link

Incomplete

Small communicating branch

Report

Papillary drainage + connection

A report should describe the observed communication status.

Prominent dorsal drainage may persist despite incomplete fusion.

Avoid inferring complete divisum when image resolution is inadequate.

Slide 24 · Divisum usually remains asymptomatic

Most

Individuals with this congenital variant have no symptoms

Many cases are incidental ductal findings.

Anatomical nonfusion alone does not establish obstructive disease.

A clinical assessment depends on actual pancreatitis or other objective findings.

Slide 25 · Pancreatitis develops in a minority

≈5%

Patients with pancreatitis, as reported by Robbins

Only about 5% develop pancreatitis.

The majority never experience the proposed drainage complication.

Do not present divisum as an inevitable cause of pancreatic injury.

Slide 26 · Why does a common variant seldom cause disease?

Anatomy

Nonfusion is common enough

Phenotype

Most remain asymptomatic

Mechanism

Outflow limitation is proposed

Modifiers

Coexisting susceptibility matters

Anatomical configuration and clinical illness are not synonymous.

The literature proposes rather than proves minor papillary obstruction in every case.

Other pancreatitis etiologies and genetic modifiers need evaluation.

Slide 27 · The proposed outflow-obstruction mechanism

Dominant dorsal flow

Relative papillary resistance

Pancreatic injury

Conceptual sequence

Most secretion passes through the minor papilla.

Limited drainage may increase ductal pressure in susceptible patients.

Obstructive stress is a proposed route to pancreatitis, not a universal outcome.

Slide 28 · Duct pressure and interstitial enzyme exposure

Impaired drainage

Increased ductal pressure

Fluid leakage / injury

Conceptual sequence

Obstructive pancreatitis to increased ductal pressure.

Enzyme-rich pancreatic fluid may leak into the interstitium.

Subsequent tissue injury may amplify inflammation.

Slide 29 · Digestion requires protected enzyme handling

Zymogens in acini

Ductal conveyance

Activation in bowel

Conceptual sequence

Digestive enzymes are predominantly synthesized as inactive precursors.

Secretion normally travels in ducts before intestinal activation.

Premature activation within pancreas predisposes to autodigestion.

Slide 30 · The role of trypsin in pancreatic injury

Early trypsin activation

Other proenzymes activate

Tissue injury

Conceptual sequence

Inappropriate intrapancreatic trypsin activity activates other enzymes.

Enzyme-mediated injury can affect parenchyma and fat.

The ensuing inflammation may further injure acinar cells.

Slide 31 · Why a duct variant is only one risk modifier

Ductal

Possible outflow resistance

Genetic

Protease regulation susceptibility

Clinical

Competing common etiologies

Inference

Assess the whole causal picture

Pancreatitis is multifactorial, including mechanical and genetic factors.

Divisum can be an anatomical contributor rather than a sufficient cause.

Clinical causation cannot be assigned from imaging alone.

Slide 32 · Genetic susceptibility: Textbook context

PRSS1

Trypsin pathway

SPINK1

Trypsin inhibition

CFTR / CASR

Duct physiology / calcium regulation

Inherited susceptibility in pancreatitis pathogenesis.

The pancreas divisum section proposes interaction with genetic defects.

A gene list is context—not a divisum-specific molecular signature.

Slide 33 · Acute pancreatitis is reversible injury

Injury

Enzyme-mediated damage

Response

Acute inflammation

Outcome

Can resolve or recur

Acute attacks involve inflammatory pancreatic parenchymal injury.

Triggering mechanisms include duct obstruction and other causes.

Divisum is considered within a broader pancreatitis differential.

Slide 34 · Repeated attacks may culminate in chronic disease

Recurrent injury

Fibrogenic response

Loss of parenchyma

Conceptual sequence

Repeated acute injury may initiate persistent remodeling.

Pancreatic stellate-cell activation promotes fibrosis.

Chronic pancreatitis involves irreversible exocrine tissue loss.

Slide 35 · Chronic pancreatitis: What pathology demonstrates

Fibrosis

Stromal replacement

Acinar dropout

Loss of exocrine tissue

Duct distortion

Altered excretory architecture

These changes describe chronic pancreatitis in general.

They are not diagnostic morphological markers of divisum itself.

Causation requires clinical, radiologic, and etiologic correlation.

Slide 36 · Divisum is not diagnosed on routine histology

Primary lesion

Duct topology

Key modality

Ductal imaging

Histology

Secondary injury if present

Limitation

No unique H&E signature

The defining finding is the arrangement of the duct systems.

Parenchymal tissue may be normal in asymptomatic divisum.

Fibrosis or acinar loss indicates chronic injury, not its specific cause.

Slide 37 · Competing causes of pancreatitis must be assessed

Mechanical

Gallstones / periampullary obstruction

Toxic

Alcohol exposure

Metabolic

Hypercalcemia / hyperlipidemia

Genetic

Inherited pancreatitis susceptibility

Multiple causes of acute pancreatic injury.

A divisum finding must not prematurely close the etiologic workup.

Common explanations may account for attacks despite coincident divisum.

Slide 38 · Clinical presentations form a spectrum

Incidental

No symptoms

Recurrent acute

Documented inflammatory attacks

Chronic injury

Structural / functional sequelae

Pain alone

Not proof of obstructed duct

Incidental divisum generally needs no intervention.

Episodes of proven pancreatitis warrant systematic etiologic review.

Pain without pancreatitis is a different management situation.

Slide 39 · First decision: Incidental or clinically implicated?

Ductal variant found

Verify clinical phenotype

Evaluate other causes

Conceptual sequence

Do not equate incidental anatomy with an actionable disease.

Recurrent documented pancreatitis raises a different question from pain alone.

Alternative and coexisting etiologies remain central.

Slide 40 · Noninvasive visualization of ductal anatomy

MRCP

Ductal fluid anatomy

S-MRCP

Secretin-enhanced visibility

EUS

Detailed pancreatic assessment

MRCP can map dominant dorsal and ventral duct pathways.

Secretin stimulation can enhance fluid signal and duct visibility.

Endoscopic ultrasound helps evaluate unexplained recurrent pancreatitis.

Slide 41 · MRCP: Follow the dorsal duct to its endpoint

SEPARATE DUCT SYSTEMS

Dorsal-derived gland

Body • tail • upper head

Ventral-derived gland

Lower / posterior head

Minor papilla

Major papilla

No communicating duct

Identify the dominant duct from the body and tail of the gland.

Trace its course to the duodenal minor papilla.

Assess whether there is a ductal connection to the ventral system.

Slide 42 · Secretin-enhanced MRCP: The physiologic principle

Secretin stimulation

More pancreatic fluid

Better duct depiction

Conceptual sequence

Secretin increases pancreatic exocrine fluid secretion.

Fluid-sensitive MR imaging accentuates duct lumen signal.

The technique may improve visualization when standard MRCP is inconclusive.

Slide 43 · MRCP and S-MRCP: Accuracy is not identical

Standard MRCP

Lower pooled sensitivity

S-MRCP

Higher pooled sensitivity

Both

High pooled specificity

2016 meta-analysis: Sensitivity 0.59 for MRCP, 0.83 for S-MRCP.

Pooled specificities were 0.99 for both approaches.

These summary estimates are context-dependent, not a universal guarantee.

Slide 44 · EUS complements ductal imaging

Unexplained attacks

EUS assessment

Complementary MRCP

Conceptual sequence

AGA 2022 prefers EUS after an unrevealing initial pancreatitis evaluation.

Contrast MRI/MRCP is a reasonable complementary or alternative test.

Local expertise and availability influence investigation choice.

Slide 45 · Beware false anatomical interpretation

Small duct

Communication may be hard to see

Chronic injury

Ductal stricture may mislead

Variant loop

Can mimic duct anatomy

Response

Correlate with expert imaging

Ductal anatomy may be incompletely visualized on standard sequences.

Stricture or an ansa loop can complicate interpretation of divisum.

An equivocal report should express uncertainty rather than overclassify.

Slide 46 · A radiology report should answer three questions

Drainage

Which papilla receives dorsal flow?

Connection

Is dorsal–ventral fusion seen?

Consequences

Dorsal dilation or santorinicele?

Context

Any alternative explanation?

The report should establish the relevant drainage topology.

Look for objective signs of potential outflow obstruction.

Interpret duct configuration alongside other pancreatic findings.

Slide 47 · ERCP is not a routine test for incidental divisum

MRCP / EUS

Diagnostic investigation

ERCP

Potential therapeutic procedure

Risk

Procedure-related pancreatitis

Noninvasive and less-invasive tests can establish duct anatomy.

ERCP has procedure-related risks and uncertain preventive benefit.

A purely incidental finding is not an indication for papillary therapy.

Slide 48 · AGA 2022: A selective endoscopic approach

Recurrent pancreatitis

Objective outflow signs?

Discuss uncertain benefit

Conceptual sequence

AGA considered minor-papilla endotherapy only in selected patients.

Possible objective markers included dorsal duct dilatation or santorinicele.

The guidance explicitly described benefit as controversial.

Slide 49 · Pain alone is not an ERCP indication

Pain only

No ERCP for divisum

Documented RAP

Evaluate etiologies

Outflow signs

Potentially relevant, not definitive

AGA 2022 states there is no role for ERCP to treat pain alone.

Symptom severity must not substitute for objective pancreatic injury.

Decisions need shared discussion of uncertainties and harm.

Slide 50 · Why sham-controlled evidence is important

Apparent response

Selection / regression effects

Controlled comparison

Conceptual sequence

Uncontrolled improvement cannot isolate benefit of papillotomy.

Recurrent pancreatitis may vary over time without intervention.

A randomized sham comparison tests benefit beyond these effects.

Slide 51 · SHARP trial: Direct test of minor papillotomy

Population

148 with divisum and RAP

Design

Randomized, sham-controlled

Intervention

ERCP + minor papillotomy

Outcome

New acute pancreatitis >30 d

The multicenter trial was published online January 2026.

Participants had unexplained recurrent acute pancreatitis and divisum.

The primary end point was subsequent acute pancreatitis after day 30.

Slide 52 · SHARP trial: No statistically significant reduction

Observed recurrence after 30 days

Minor papillotomy

34.7%

Sham ERCP

43.8%

Trial: N = 148; Adjusted HR 0.83 (95% CI 0.49–1.41)

Papillotomy: 26/75 patients (34.7%) developed acute pancreatitis.

Sham: 32/73 patients (43.8%) developed acute pancreatitis.

Adjusted HR 0.83 (95% CI 0.49–1.41): Benefit was not established.

Slide 53 · SHARP trial: Procedure-related injury matters

Papillotomy arm

11/75 acute attacks ≤30 d

Sham arm

6/73 acute attacks ≤30 d

Interpretation

Consider procedural harm

Acute pancreatitis within 30 days occurred in both trial groups.

The papillotomy arm had numerically more early attacks.

Risk–benefit decisions must include ERCP complications.

Slide 54 · How the 2026 trial changes clinical interpretation

AGA 2022

Endotherapy: Uncertain, selective

JAMA 2026

No demonstrated preventive effect

Practice reasoning

Avoid routine minor papillotomy

Older expert advice allowed carefully selected minor papillary intervention.

The newer sham-controlled trial did not show significant prophylactic benefit.

Evidence should be updated without rewriting what Robbins actually states.

Slide 55 · Evidence limits: Do not overgeneralize SHARP

Studied

Idiopathic recurrent acute pancreatitis

Excluded

Other etiologies / calcific CP

Interval

Outcome beyond 30 days

Inference

Applies to trial-like populations

The trial was not a study of all patients with divisum.

Its results do not imply every duct intervention is ineffective in all contexts.

It does challenge routine papillotomy to prevent recurrent attacks.

Slide 56 · Vignette: Incidental ductal variant

TEACHING VIGNETTE (HYPOTHETICAL)

Asymptomatic patient

MRCP shows dorsal-to-minor drainage

No documented pancreatitis

First establish that the finding is incidental.

The anatomical variant alone is not evidence of ductal obstruction.

Avoid unnecessary ERCP or elective minor-papilla intervention.

Slide 57 · Vignette: Recurrent acute pancreatitis

TEACHING VIGNETTE (HYPOTHETICAL)

Multiple documented acute attacks

Divisum on ductal imaging

Other causes incompletely assessed

The proper task is a comprehensive etiologic assessment.

Evaluate gallstone, alcohol, metabolic and inherited susceptibility.

Do not assume a minor papillotomy will prevent recurrence.

Slide 58 · Vignette: Fibrosis with pancreas divisum

TEACHING VIGNETTE (HYPOTHETICAL)

Chronic pancreatic insufficiency

Fibrosis / acinar dropout

Divisum detected on MRCP

Fibrosis establishes chronic pancreatic injury, not its cause.

The pancreatic ductal variant may be contributory or incidental.

Seek other etiologies and objective evidence of outflow abnormality.

Slide 59 · Differentiate the nearby congenital anomalies

Divisum

Failure of duct fusion

Annular pancreas

Encircles 2nd duodenum

Ectopic pancreas

Pancreatic tissue at other sites

Annular pancreas can produce duodenal obstruction.

Ectopic pancreas is heterotopic pancreatic tissue, often incidental.

Only divisum is defined by dominant dorsal drainage to the minor papilla.

Slide 60 · Clinical interpretation: Five essential distinctions

Anatomic

Divisum ≠ disease

Frequency

Common variant ≠ common pancreatitis

Causality

Coexistence ≠ proof

Procedure

ERCP ≠ benign diagnostic test

A fifth distinction is evidence: Expert consensus differs from randomized outcomes.

Record the precise observed duct pattern and clinical phenotype.

Use a complete pancreatitis evaluation before attributing causation.

Slide 61 · Review questions: Anatomy and clinical decisions

TEACHING VIGNETTE (HYPOTHETICAL)

Most pancreatic output in divisum?

What defines complete divisum?

ERCP for pain alone?

Dorsal-derived gland → duct of Santorini → minor papilla.

Complete divisum lacks an interductal dorsal–ventral connection.

Pain alone does not justify ERCP for pancreas divisum.

Slide 62 · Pancreas divisum: Integrated conclusions

Nonfusion

Dominant minor outlet

Usually asymptomatic

Conceptual sequence

Robbins: Congenital ductal nonfusion; Reported frequency 3–10%.

An outflow contribution to pancreatitis is proposed in a minority.

JAMA 2026: Routine minor papillotomy did not demonstrate preventive benefit.

Slide 63 · Selected references and source boundaries

Textbook

Robbins 11e, Ch 19 (2026)

Imaging

Shen et al., Sci Rep 2016

Guidance

AGA CPU, Gastro 2022

Trial

JAMA SHARP, 2026

Primary anatomical and pathology teaching derives from Robbins.

Diagnostic imaging and procedural advice are documented external context.

The 2026 randomized trial informs, but does not replace, the textbook anatomy.

Core anatomical text: Robbins 11th edition; diagnostic and trial findings: cited supplementary studies.