Histo: Diseases of the Pancreas and Gallbladder

Question 1

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

Answer 1

Acini (secrete enzymes) 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 50%, tumour, trauma)
• Metabolic/toxic (alcohol 33%, drugs, hypercalcaemia, hyperlipidaemia)
• Poor blood supply (shock, hypothermia)
• Infection/inflammation (viruses e.g. mumps)
• Autoimmune (IgG4)
• Idiopathic

Question 4

Which drug to ask about in acute pancreatitis?

Answer 4

thiazide- very common

Question 5

Describe how alcohol can cause acute pancreatitis.

Answer 5

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 6

Patterns of injury and their causes

Answer 6

periductal: necrosis near duct- obstruction
perilobular: near edge of lobules- blood supply
panlobula: severe

Question 7

How does gallstone obstruction cause pancreatitis?

Answer 7

obstruction of the common bile duct, reflux into the acini causing damage

Question 8

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

Answer 8

• 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 9

Outline the pathway of inflammation in acute pancreatitis.

Answer 9

Activated enzymes → acinar necrosis → release of more enzymes

Question 10

What is saponification?

Answer 10

• Lipases break down fats to release free fatty acids
• Calcium binds to the free fatty acids forming soaps (yellow-white foci)- fat necrosis

Question 11

List some complications of acute pancreatitis.

Answer 11

• Pseudocyst formation, abscesses
• Shock
• Hypoglycaemia
• Hypocalcaemia

prognosis mortality up to 50% for haemorrhagic panc

Question 12

Define pseudocyst.

Answer 12

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

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

Question 13

List some causes of chronic pancreatitis.

Answer 13

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

Question 14

Outline the pattern of injury in chronic pancreatitis.

Answer 14

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

Question 15

List some complications of chronic pancreatitis.

Answer 15

• Malabsorption
• Diabetes mellitus
• Pseudocysts
• Pancreatic carcinoma

Question 16

What is the characteristic feature of autoimmune pancreatitis?

Answer 16

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

Question 17

How is autoimmune pancreatitis treated?

Answer 17

Steroids - usually responds well

Question 18

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

Answer 18

• Ductal (85%), 5% cancer deaths, 2M: 1F, 5% 5 year survival
• 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)

also cystic neoplasms and pancreatic neuroendocrine tumours

Question 19

Name two types of cystic neoplasm of the pancreas.

Answer 19

• Serous cystadenoma
• Mucinous cystadenoma

Question 20

List some risk factors for pancreatic cancer.

Answer 20

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

Question 21

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

Answer 21

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

Question 22

Which mutation is very common in pancreatic cancer?

Answer 22

K-ras (95%)

Question 23

Describe the macroscopic appearance of ductal carcinoma?

Answer 23

Gritty and grey

Invades adjacent structures

NOTE: tumours in the head of the pancreas present earlier

Question 24

Describe the microscopic appearance of ductal carcinoma.

Answer 24

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

Question 25

What is the most common site of ductal carcinoma?

Answer 25

Head (60%) NOTE: neuroendocrine tumours are more common in the tail body, tail, diffuse - other sites

Question 26

How do ductal carcinomas spread?

Answer 26

lots of ways but perineural also an option

Question 27

What are the usual sites of metastasis of ductal carcinoma?

Answer 27

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

Question 28

List some complications of ductal carcinoma.

Answer 28

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

Question 29

By what mechanism does pancreatic cancer cause migratory thrombophlebitis?

Answer 29

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

Question 30

List some key features of pancreatic neuroendocrine neoplasms.

Answer 30

* 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 31

What is the most common type of functional neuroendocrine tumour?

Answer 31

Insulinoma commonest type of secretory tumour

Question 32

List some factors that increase the likelihood of developing gallstones.

Answer 32

* Age- older * Gender (females) * Ethnic factors- native americans * Hereditary- disorder of bile metabolism * Drugs (e.g. oral contraceptive) * acquired disorders- rapid weight loss

Question 33

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

Answer 33

* Cholesterol * May be single * Mostly radiolucent (NOT seen on AXR) * More than 50% cholesterol * Pigment * Often multiple * Contain calcium salts of unconjugated bilirubin * Mostly radio-opaque

Question 34

List some complications of gallstones.

Answer 34

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

Question 35

Acute cholecystitis

Answer 35

90% gallstones, acalculous: salmonella

Question 36

chronic cholecystitis causes

Answer 36

chronic inflammation fibrosis diverticula 90% have gallstones

Question 37

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

Answer 37

* Rokitansky-Aschoff sinuses - form as a result of the gallbladder contracting against an obstruction * mucosa been pushed out due to raised pressure

Question 38

Which type of cancer is gallbladder cancer?

Answer 38

Adenocarcinoma 90% associated with gallstones NOTE: it is technically a type of cholangiocarcinoma