HISTO: Pancreas and gallbladder Flashcards
Pancreatic microanatomy
What are the two types of tissue seen on histology in the pancreas?
Excorine
Endocrine
What is acute pancreatitis?
Acute inflammation of the pancreas caused by aberrant release of pancreatic enzymes. Relatively common, incidence increasing.
What are the causes of acute pancreatitis? What are the two most common causes.
Duct obstruction = Gall stones (50%), Trauma, Tumours
Metabolic/toxic = Alcohol (33%) (5% of alcoholics develop acute pancreatitis); Drugs (e.g. thiazides); Hypercalcaemia, Hyperlipidaemia
Poor blood supply = Shock, Hypothermia
Infection/ inflammation - Viruses (e.g. mumps)
Autoimmune
Idiopathic (15%)
What are the two mechanisms of pathogenesis of acute pancreatitis?
- Duct obstruction- due to gallstones and alcohol
- Direct acinar injury - all other causes
What is the pathogenesis of duct obstruction causing acute pancreatitis?
Gallstone stuck distal to where the common bile duct and pancreatic ducts join
—> reflux of bile up the pancreatic duct —> damage to acini and release of proenzymes which then become activated
How does alcohol cause acute pancreatitis?
Alcohol –> spasm/oedema of Sphincter of Oddi + formation of a protein rich pancreatic fluid –> obstructs the pancreatic ducts
What are the 3 pattens of injury in acute pancreatitis?
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 – develops from 1. and 2.
How do activated enzymes e.g. lipases, cause these patterns of injury?
Activated enzymes –> acinar necrosis –> enzyme release etc.
Ranges from stromal oedema, to haemorrhagic necrosis
e.g. Lipases –> fat necrosis (calcium ions bind to free fatty acids forming soaps which are seen as yellow white foci)
What are the complications of acute pancreatitis?
Pancreatic : pseudocyst, abscess
Systemic: shock, hypoglycaemia, hypocalcaemia
What is the prognosis for acute pancreatitis?
Overall mortality up to 50% for haemorrhagic pancreatitis (due to association with systemic shock)
What is shown?
Yellow white foci when calcium ions bind to fatty acids forming soaps
What is chronic pancreatitis? How common is it?
Relapsing or persistent, associated with acute pancreatitis in half of cases
Relatively uncommon
Mortality 3% per year
What are the causes of chronic pancreatitis? What is the most common cause?
Metabolic/toxic = Alcohol (80%); Haemochromatosis
Duct obstruction = Gallstones; Abnormal pancreatic duct anatomy; Cystic fibrosis (“mucoviscoidosis”)
Tumours
Idiopathic Autoimmune
What is the pathogenesis of chronic pancreatitis?
Same as for acute pancreatitis
What is the pattern of injury seen in chronic pancreatitis?
Chronic inflammation with parenchymal fibrosis and loss of parenchyma
Duct strictures with calcified stones with secondary dilatations
What are the complications of chronic pancreatitis?
- Malabsorption
- Diabetes mellitus
- Pseudocyts
- Carcinoma of the pancreas - chronic pancreatitis may be a risk factor for this
What is shown?
Calcification - could be either acute or chronic
What are the cells in the middle in this slide of chronic pancreatitis?
Rounded areas are endocrine cells which survive well - although there is a risk of diabetes over time
What are pancreatic pseudocysts associated with?
Associated with acute and/ or chronic pancreatitis
What are the characteristics of pancreatis pseudocysts?
Lined by fibrous tissue (no epithelial lining), contain fluid rich in pancreatic enzymes or necrotic material
Connect with pancreatic ducts
May resolve, compress adjacent structures, become infected or perforate
What is a characteristic of IgG4 related disease? What parts of the body may be affected?
Characterised by large numbers of IgG4 positive plasma cells.
May involve the pancreas, bile ducts and almost any other part of the body
What disease is represented here?
IgG4 related disease
What are 3 types of tumours of the pancreas?
Carcinomas
- Ductal (85% of all neoplasms)
- Acinar
Cystic neoplasms
- Serous cystadenoma
- Mucinous cystic neoplasm
Pancreatic neuroendocrine tumours (Islet cell tumours)
What is the most common type of pancreatic tumour?
Ductal carcinomas (85% of all)
What is the prognosis with ductal carcinoma in the pancreas?
- 5% of cancer deaths
- Increasingly common with age, 2M: 1F
- 5 year survival: 5%
What are 3 risk factors for pancreatic carcinomas?
- Smoking
- BMI and dietary factors
- Chronic pancreatitis
- Diabetes
What mutations are common in pancreatic ductal carcinomas? How do these cancers arise?
Arise from dysplastic ductal lesions:
- Pancreatic Intraductal Neoplasia (PanIN)
- Intraducal Mucinous Papillary Neoplasm
K-Ras mutations in 95% of cases
What is the macroscopic appearance of ductal carcinomas of the pancreas?
- Gritty and grey
- Invades adjacent structures
- Tumours in the head present earlier
What are the microscopic features of ductal carcinomas of the pancreas?
Adenocarcinomas: mucin secreting glands set in desmoplastic stroma
Where do most ductal carcinomas of the pancreas arise?
- Head (60%)
- Body
- Tail
- Diffuse
Where do pancreatic ductal carcinomas spread to?
- Direct: Bile ducts, duodenum
- Lymphatic: Lymph nodes
- Blood: Liver
- Serosa: Peritoneum
Perineural?
What are the complications of pancreatic ductal carcinomas?
Complications are due to spread
- Chronic pancreatitis
- Venous thrombosis (“migratory thrombophlebitis”)
What are the two types of cystic tumours of the pancreas? What are their features?
Are made of serous or mucinous secreting epithelium (cf. ovarian tumours)
Usually benign
What are the features of this pancreatic cystic tumour?
- Benign
- Sharply demarcated
- Does nt invade locally or distally
Are most pancreatic endocrine neoplasms secretory or non-secretory?
Non-secretory in most cases except for insulinomas
Give an example of a neuroendocrine marker which can be used to screen for pancreatic endocrine tumours?
Contain neuroendocrine markers e.g. chromogranin
What is a genetic cause of pancreatic endocrine neoplasms?
may be associated with the Multiple Endocrine Neoplasia (MEN) 1 syndrome
What is the problem with pancreatic endocrine tumours?
behaviour difficult to predict
What is the most common secretory tumour of the pancreas?
Insulinoma - derived from beta cells
Commonest type of secretory tumour
How common is cholelithiasis?
20% of adults in the West
What are the risk factors for gall stones?
- Age and gender: increasing age, F>M
- Ethnic and geographic: e.g. Native Americans
- Hereditary: e.g. disorders of bile metabolism
- Drugs e.g. oral contraceptive
- Acquired disorders e.g. rapid weight loss
What are the types of gall stones? How do they appear on imaging?
Cholesterol (>50% cholesterol) = may be single, mostly radiolucent
Pigment (contain calcium salts of unconjugated bilirubin) = multiple, mostly radio-opaque
What are the complications of gall stones?
- Bile duct obstruction
- Acute and chronic cholecystitis
- Gall bladder cancer
- Pancreatitis
What is acute cholecytitis most associated with?
= acute inflammation
90% associated with gall stones
What are the histopathological features of chronic cholecystitis?
= chronic inflammation
- Fibrosis
- Diverticula – Rokitansky-Aschoff sinuses
- 90% contain gall stones
What is the thickness of a normal gall bladder wall?
2mm
What is this feature of chornic cholecystitis?
Diverticula - Rokitansky-Aschoff sinsus
What are the most common types of gall bladder cancer? What is this cancer most associated with?
Adenocarcinomas
90% associated with gall stones
Ductal adenocarcinoma
empty answer
haemolytic anaemia
