Non-Neoplastic Pancreas

Benjamin Swanson, MD, PhDAssistant Professor, Department of PathologyBenjamin.Swanson@osumc.edu

Learning Objectives

1. Define pancreas divisum, explain its embryologic origin and clinical manifestations.

2. Define annular pancreas, its clinical presentation and embryologic origin.

3. Describe the conditions, etiologic agents, clinical manifestations, and complications associated with acute and chronic pancreatitis.

4. Understand the underlying pathophysiology resulting in the global manifestations of acute pancreatitis.

Congenital Anomalies

Agenesis, hypoplasia Annular Pancreas divisum Aberrant pancreas (ectopic) Duct anomalies

Annular Pancreas

Pancreas arises from dorsal and ventral duodenal buds

In the 6th week of normal pancreas development, the ventral pancreas with the common bile duct, rotates around the posterior duodenum

In annular pancreas, a portion of the ventral primordium becomes fixed to the duodenum while the other portion rotates around the duodenum

Pancreas

Annular Pancreas

This remnant forms a band-like ring around the the second portion of the duodendum

Can present as duodenal obstruction with gastric distension and vomiting

Pancreas Divisum

Most common congenital anomaly of the pancreas (5-10% of population)

Caused by an anomaly in the fusion of the duct systems of the primordial ventral and dorsal pancreas

In complete divisum, the larger portion of the pancreas drains through the minor papilla stenosis may predispose to pancreatitis

Complete Partial

Acute Pancreatitis Can occur at any age Most commonly occurs in 3rd to 6th decade of life Early presentation (1st decade of life) hereditary,

infection or trauma Mild “edematous” pancreatitis

Minimal organ dysfunction Uneventful recovery in 5-7 days

Severe “necrotizing” pancreatitis Multisystem organ failure (Acute respiratory distress syndrome,

Acute tubular necrosis of the kidney, Disseminated intravascular coagulation, Sepsis)

Abscess and pseudocyst formation Duodenal obstruction Mortality ~10%

Acute Pancreatitis Etiology Alcohol Gallstones Metabolic disorders (hyperlipidemia, hypercalcemia) Medications Infections:

Viral: Mumps, coxsackie, hepatitis B, CMV, varicella-zoster, HSV, HIV

Bacteria: mycoplasma, Legionella, Leptospira, salmonella Fungi: Aspergillus Parasites: Toxoplasma, cryptosporidium, Ascaris

Trauma/post-procedural Vascular/shock Congenital: Pancreatic divisum Genetic: Cystic Fibrosis, alpha-1 antitrypsin deficiency

Account for most cases (60-75%)

Pathophysiology of Acute pancreatitis

Acute PancreatitisMacroscopic Findings

Mild acute pancreatitis Swollen pale and indurated

pancreas Lobules appear separated

by edema Focal fat necrosis

Severe acute pancreatitis Large confluent areas of fat

necrosis Hemorrhagic necrosis may

develop

Acute PancreatitisMicroscopic Findings

Mild acute pancreatitis Interstitial acute

inflammation Spotty peripancreatic fat

necrosis

Severe acute pancreatitis Abundant neutrophils Large areas of fat necrosis Variable levels of pancreatic

necrosis Saponification

Chronic PancreatitisIncidence

Can occur at any age Alcohol related chronic pancreatitis more commonly

affects males >40 yo Chronic pancreatitis in childhood represents hereditary

etiologies

Chronic PancreatitisEtiology

Chronic alcohol ingestion Most common cause in developed countries (70%) Only 10% of alcohol abusers develop chronic pancreatitis which

suggests additional factors account for its development Concurrent smoking may multiple the risk of chronic pancreatititis

with 10X

Duct obstruction: choledocholithiasis, tumors, scarring/stenosis

Groove pancreatitis (paraduodenal wall cyst) Metabolic: hypercalcemia, hyperlipidemia

Chronic PancreatitisEtiology Tropical

Aggressive form of juvenile pancreatitis which occurs in tropical developing countries

May be related to malnutrition, toxins or genetic predisposition

Hereditary: PRSS1, CFTR, SPINK1 Trauma Idiopathic: up to 25% of cases

Chronic PancreatitisMacroscopic Findings Pancreas may be involved focally, diffusely, or

segmentally Affected pancreas usually firm, indurated and fibrotic Cystically dilated pancreatic ducts

Chronic PancreatitisMicroscopic Findings Preserved lobular arrangement of the pancreas Duct and acinar atrophy leads to more prominent

appearing islets of Langerhans Pancreatic duct alterations

Atrophy (can be angulated) Hyperplasia (pseudopapillary or papillary) Metaplasia (squamous, mucinous, pyloric)

Fibrosis Chronic inflammation

Chronic PancreatitisAcinar Atrophy

Chronic PancreatitisFibrosis and Chronic Inflammation

Chronic PancreatitisSpared Islets

Pancreatic Pseudocyst

Occurs as a result of pancreatitis (acute or chronic) Most commonly associated with alcohol consumption Grossly is a unilocular cyst with a ragged inner surface

and a thick fibrotic wall Fluid within the cyst has few cells and has high levels of

the enzyme amylase

Pancreatic Pseudocyst

Microscopically lacks an epithelial lining (thus pseudocyst). Cyst wall lined by granulation tissue

Microscopically also lacks necrosis (as opposed to an abscess)

Summary

Pancreatic divisum is a complete or partial division of the pancreas, it is caused by lack of fusion of the two embryologic duodenal buds

Annular pancreas is an encircling of the duodenum by the pancreas, it is caused by failure of the ventral duodenal bud to properly rotate with the duodenum

Acute pancreatitis is most commonly caused by alcohol or gallstones; it microscopically shows acute inflammation and necrosis

Chronic pancreatitis microscopically shows fibrosis, acinar atrophy and chronic inflammation

Non neoplastic pancreas quiz

Thank you for completing this module

Questions? Contact me at:

Benjamin.Swanson@osumc.edu

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