The Pathology of the Pancreas Flashcards
Which portion of the pancreas secretes digestive enzymes into the duodenum?
The exocrine pancreas
What are the parts of the exocrine pancreas?
Acinar and centroacinar (ductal) cells with associated connective tissue, vessels, and nerves
What % of the pancreatic mass is exocrine?
More than 95%
Where do the hormones of the endocrine part of the pancreas empty?
Straight into the bloodstream
What is agenesis of the pancreas?
It is an extremely rare congenital condition that results from defective pancreatic formation
What is the pathogenesis of agenesis of the pancreas?
Mutation of the PDX1 gene, located on chromosomal locus 13q12.1
What are the different types of agenesis?
Partial and complete agenesis
What is partial agenesis?
The pancreas body is of varied size, a remnant of the accessory duct exists and the minor papilla is present
What is complete agenesis?
The neck, body, and tail of the pancreas are absent, as well as the accessory duct and the minor duodenal papilla
What is the most common congenital abnormality?
Pancreas divisum (3 to 10%)
What is pancreas divisum? What is the result of it?
Dorsal and ventral pancreatic ducts fail to fuse. Thus, the main pancreatic duct only drains a small portion of the head of the gland
Where does the bulk of the pancreas drain into in the pancreas divisum?
Drains through the minor sphincter, which is a narrow opening
What can pancreas divisum lead to?
Acute/chronic pancreatitis
What is annular pancreas?
When a ring of pancreatic tissue completely encircles the duodenum
What is the risk associated with an annular pancreas?
Duodenum obstruction
What is an ectopic pancreas?
Heterotopic pancreatic tissue occurs in 2 to 15% of the population
Pancreatic tissue lies outside and separates into the pancreatic gland
What are the common sites where pancreatic tissue can be found in the ectopic pancreas?
Stomach & duodenum
Jejunum
Ileum
What is a congenital cyst?
Faulty development of pancreatic duct
What is the morphology of the congenital cyst?
Unilocular cyst (up to 5cm)
Lined by either uniform cuboidal or flattened epithelium
Enclosed in a thin, fibrous capsule
What is pancreatitis?
Inflammatory disorders of the pancreas
What are the congenital abnormalities, involving the pancreas?
Ectopic Pancreas
Congenital Cyst
Annular Pancreas
Pancreas divisum
Agenesis
What is acute pancreatitis?
Inflammation and hemorrhage but function can return to normal if the underlying cause of inflammation is removed
What is chronic pancreatitis?
Inflammatory disorder with irreversible destruction of exocrine pancreatic parenchyma
How does acute pancreatitis occur?
It is due to the autodigestion of pancreatic parenchyma by pancreatic enzymes (premature activation of trypsin leads to activation of other pancreatic enzymes)
What is the incidence of acute pancreatitis?
10 to 20% per 100000
What is the male-female ratio for acute pancreaitis?
1:3 with gallstones
6:1 with alcoholism
What are the causes of acute pancreatitis ?
Non-traumatic
Traumatic
Idiopathic
What are the non-traumatic causes of acute pancreatitis?
Biliary tract disease
Alcohol
Viral Infections (EBV, CMV)
Hyperlipidemia
Hyperparathyroidism
75% of cases
What are the traumatic causes of acute pancreatitis?
Operative trauma
Endoscopic procedure with fye injection
5%
What is the % of cases of acute pancreatitis due to idiopathic causes?
20%
What is the pathogenesis of acute pancreatitis?
This can occur as a result of inappropriate activation of pancreatic enzymes
This leads to autodigestion of the pancreas and triggers an inflammatory cascade
Can result in necrosis both within the pancreas itself and extra-pancreatic adipose tissue
What can cause acinar cell injury? How does that lead to acute pancreatitis?
Viral infections, drugs and direct trauma
Direct damage to acinar cells
What can cause duct obstruction and how does it lead to acute pancreatitis?
Gallstones and Chronic alcoholism
- Blocks ductal flow
- Increases intraductal pressure
- Allows accumulation of enzyme-rich intestinal fluid
- Injured tissues, periacinar myofibroblasts, and leukocytes then release pro-inflammatory cytokines
- Promote local inflammation and interstitial edema through a leaky microvasculature
- Edema further compromises local blood flow
- Vascular insufficiency and ischemic injury to acinar cells
What can cause defective intracellular transport and how does it lead to acute pancreatitis?
Metabolic injury
- Pancreatic proenzyme and lysosomal hydrolases become packaged together
- Results in proenzyme activation, lysosomal rupture, and local release of activated enzymes
- Acinar cell injury
What occurs in normal acinar cells?
Digestive enzymes intended for zymogen granules and hydrolytic enzymes destined for lysosomes are transported in discrete pathways after synthesis in the endoplasmic reticulum
What are the basic alteration in the morphology of acute pancreatitis? (5)
- Microvascular leakage due to edema
- Necrosis of fat by lipases
- Acute inflammatory reaction
- Proteolytic destruction of pancreatic parenchyma
- Destruction of blood vessels leading to intestinal hemorrhage
What is the morphology in mild acute pancreatitis?
Acinar cell necrosis, intense acute inflammation and foci of necrotic adipocytes
What does the fat necrosis result from in mild acute pancreatitis?
Enzymatic destruction of fat cells, released faty acids combine with calcium to form insoluble salts that precipitate in situ
What is the pathogenesis of severe acute pancreatitis?
Becrisus of pancreatic tissue affects acinar, ductal tissues and islets of Langerhans
That causes vascular damage
Which causes hemorrhage into the parenchyma of the pancreas
What are the gross-features of severe acute pancreatitis?
The pancreas exhibits red black hemorrhagic areas interspersed with foci of yellow-white chalky fat necrosis
What are the most common signs and symptoms of acute pancreatitis?
Severe epigastric pain RADIATING to the back
Nausea, vomiting, diarrhea and loss of appetite
Fever and chills
Hemodynamic instability
What are the signs and symptoms in severe cases of acute pancreatitis?
Tenderness, guarding and rebound
What are the signs of acute pancreatitis which are less common?
Grey-Turner’s sign (hemorrhagic discolouration of the flanks)
Cullen’s sign (Hemorrhagic discolouration of the umbilicus)
What is the CT apperance of Grade A acute pancreatitis ?
Normal CT
What is the CT apperance of Grade B acute pancreatitis ?
Focal or diffuse enlargement of the pancreas
What is the CT apperance of Grade C acute pancreatitis?
Pancreatic gland abnormalities and peripancreatic inflammation
What is the CT apperance of Grade D acute pancreatitis ?
Fluid collection in a single location
What is the CT apperance of Grade E acute pancreatitis ?
Two or more fluid collections and/or gas bubbles in or adjacent to pancreas
What is the necrosis score?
No necrosis = 0
0 to 30% = 2
30 to 50% = 4
Over 50% = 6
What are the complication of acute pancreatitis?
Fluid collections associated with intestitial edematous pancreatitis
Fluid collections associated with necrotsising pancreatitis
What is pancreatic fluid collection?
In the first 4 weeks; non - encupasulated pancreatic fluid collections
What are pseudocysts?
Develop after 4 weeks; encapsulated peripancreatic or remote fluid collections
What is acute necrotic collection?
In the first 4 weeks; non-encapsulated heterogenous non-liquefied material
What is walled-off necrosis?
Develop after 4 weeks; encapsulated heterogenous non-liquefied material