Histo: Diseases of the Pancreas and Gallbladder

Question 1

What are the main components of the exocrine part of the pancreas?

Answer 1

Acini and ducts

Question 2

Define acute pancreatitis.

Answer 2

Acute inflammation of the pancreas caused by aberrant release of pancreatic enzymes

Question 3

List some causes of acute pancreatitis.

Answer 3

• Duct obstruction (gallstones, tumour, trauma)
• Metabolic/toxic (alcohol, drugs, hypercalcaemia, hyperlipidaemia)
• Poor blood supply
• Infection/inflammation (viruses e.g. mumps)
• Autoimmune
• Idiopathic

Question 4

Describe how alcohol can cause acute pancreatitis.

Answer 4

It leads to spasm/oedema of the sphincter of Oddi and the formation of protein-rich pancreatic fluid which is thick and causes an obstruction

NOTE: most other causes of acute pancreatitis will do so via direct acinar injury

Question 5

Describe the three main patterns of injury in acute pancreatitis and describe what they result from.

Answer 5

• Periductal - necrosis of acinar cells near ducts (usually secondary to obstruction)
• Perilobular - necrosis at the edges of the lobules (usually due to poor blood supply)
• Panlobular - results from worsening periductal or perilobular inflammation

Question 6

Outline the pathway of inflammation in acute pancreatitis.

Answer 6

Activated enzymes → acinar necrosis → release of more enzymes

Question 7

What is saponification?

Answer 7

• Lipases break down fats to release free fatty acids
• Calcium binds to the free fatty acids forming soaps

Question 8

List some complications of acute pancreatitis.

Answer 8

• Pseudocyst formation, abscesses
• Shock
• Hypoglycaemia
• Hypocalcaemia

Question 9

Define pseudocyst.

Answer 9

• A collection of fluid without an epithelial lining
• They are rich in pancreatic enzymes and necrotic material
• They are lined by fibrous tissue

NOTE: they may resolve, compress adjacent structures, become infected or perforate

Question 10

List some causes of chronic pancreatitis.

Answer 10

• Metabolic/Toxic: alcohol (80%), haemochromatosis
• Duct obstruction: gallstones, abnormal anatomy, cystic fibrosis (mucoviscoidosis)
• Tumours
• Idiopathic

Question 11

Outline the pattern of injury in chronic pancreatitis.

Answer 11

• Chronic inflammation with parenchymal fibrosis and loss of parenchyma
• There will be duct strictures with calcified stones with secondary dilatations

Question 12

List some complications of chronic pancreatitis.

Answer 12

• Malabsorption
• Diabetes mellitus
• Pseudocysts
• Pancreatic carcinoma

Question 13

What is the characteristic feature of autoimmune pancreatitis?

Answer 13

Large numbers of IgG4 positive plasma cells typically found around the ducts

Question 14

How is autoimmune pancreatitis treated?

Answer 14

Steroids - usually responds well

Question 15

What are the two types of pancreatic cancer and which is more common?

Answer 15

• Ductal (85%)
• Acinar (15%)

NOTE: many ductal carcinomas may actually arise from acini after a process called acini-ductal metaplasia (these ductal carcinomas have a different natural history to truly ductal carcinomas)

Question 16

Name two types of cystic neoplasm of the pancreas.

Answer 16

• Serous cystadenoma
• Mucinous cystadenoma

Question 17

List some risk factors for pancreatic cancer.

Answer 17

• Smoking
• BMI and dietary factors
• Chronic pancreatitis
• Diabetes mellitus

Question 18

Name two types of dysplastic precursor lesion that ductal carcinoma can arise from.

Answer 18

• Pancreatic intraductal neoplasia (PanIN)
• Intraductal mucinous papillary neoplasm

Question 19

Which mutation is very common in pancreatic cancer?

Answer 19

K-ras (95%)

Question 20

Describe the macroscopic appearance of ductal carcinoma?

Answer 20

Gritty and grey

Invades adjacent structures

NOTE: tumours in the head of the pancreas present earlier

Question 21

Describe the microscopic appearance of ductal carcinoma.

Answer 21

• Adenocarcinomas (secrete mucin and form glands)
• Mucin-secreting glands are set in desmoplastic stroma

Question 22

What is the most common site of ductal carcinoma?

Answer 22

Head (60%)

NOTE: neuroendocrine tumours are more common in the tail

Question 23

What are the usual sites of metastasis of ductal carcinoma?

Answer 23

• Direct: bile ducts, duodenum
• Lymph nodes
• Blood: liver
• Serosa: peritoneum

Question 24

List some complications of ductal carcinoma.

Answer 24

• Metastasis
• Chronic pancreatitis
• Venous thrombosis (migratory thrombophlebitis)

Question 25

By what mechanism does pancreatic cancer cause migratory thrombophlebitis?

Answer 25

• Circulating pancreatic cancer cells release mucous which activates the clotting cascade

Question 26

List some key features of pancreatic neuroendocrine neoplasms.

Answer 26

• Usually non-secretory
• Contains neuroendocrine markers (e.g. chromogranin - can be measured as a screening test for neuroendocrine tumours)
• May be associated with MEN1

Question 27

What is the most common type of functional neuroendocrine tumour?

Answer 27

Insulinoma

Question 28

List some factors that increase the likelihood of developing gallstones.

Answer 28

• Age
• Gender (females)
• Ethnic factors
• Hereditary
• Drugs (e.g. oral contraceptive)

Question 29

What are the two types of gallstone and what are their distinguishing features?

Answer 29

• Cholesterol
  
  • May be single
  • Mostly radiolucent (NOT seen on AXR)
• Pigment
  
  • Often multiple
  • Contain calcium salts of unconjugated bilirubin
  • Mostly radio-opaque

Question 30

List some complications of gallstones.

Answer 30

• Most are asymptomatic
• Bile duct obstruction
• Acute and chronic cholecystitis
• Gallbladder cancer
• Pancreatitis

Question 31

What is the term used to describe diverticula of the gallbladder? How do they form?

Answer 31

• Rokitansky-Aschoff sinuses - form as a result of the gallbladder contracting against an obstruction

Question 32

Which type of cancer is gallbladder cancer?

Answer 32

Adenocarcinoma

NOTE: it is technically a type of cholangiocarcinoma