Histopathology - Pancreas and gallbladder Flashcards
Which component of the pancreas is the first to be affected in chronic pancreatitis?
Exocrine component
The islets of Langerhans are part of which component of the pancreatic system?
The endocrine system
A cells - glucagon to increase blood glucose
B cells - insulin to decrease blood glucose
D cells - somatostatin to regulate a and B cells
D1 - vasoactive peptide, stimulates secretion of water into pancreatic system
PP - pancreatic polypeptide, self regulates secretion activities
Which cells are part of the exocrine system?
Ducts and acinar cells
Commonest causes of acute pancreatitis
Gallstones 50%
Duct obstruction —> bile reflux up the pancreatic duct — damage of acinar cells — release of pro enzymes which then become activated
Alcohol 33%
Spasm of the sphincter of Oddi — formation of protein reich pancreatic fluid — obstruction of the pancreatic duct
Electrolyte imbalance that causes pancreatitis + electrolyte imbalance that is cause by pancreatitis
Hypercalcaemia causes pancreatitis
Pancreatitis causes hypocalcaemia (released FFA bind to free calcium)
Therefore if hypercalcaemia is the cause of acute pancreatitis, calcium levels falls down to normal in acute pancreatitis
Periductal vs perilobular injury in acute pancreatitis
Periductal - secondary to obstruction (necrosis of acinar cells near ducts)
Perilobular - due to ischaemia (necrosis at the edges of the lobules)
(Panlobular develops from both periductal and perilobular
Which scoring system is used is used to score pancreatitis?
Glasgow
> = 3 indicates severe pancreatitis
Commonest cause of chronic pancreatitis
Alcohol 80%
Pathogenesis of acute pancreatitis
Duct obstruction (gallstones + alcohol)
Direct acinar injury (all the rest)
Presentation of chronic pancreatitis
Epigastric pain
Malabsorption - weight loss, steatorrhoea
DM
Chronic pancreatitis hsitology
Loss of exocrine tissue
Calcification (diagnostic of chronic pancreatitis)
Fibrosis
Duct strictures with calcified stones with secondary duct dilations
What is a pancreatic pseudocyst?
Lined by fibrous tissue
Contain pancreatic enzymes or necrotic material
Connect with pancreatic ducts
Antibody related to autoimmune pancreatitis
IgG4
Produced by IgG4 plasma cells
Commonest tumour of the pancreas
Ductal (85%) (k-ras mutation)
The rest are acinar (increased serum lipase)
Marker of pancreatic damage
Lipase > amylase
Which cells do most cancers of the pancreas arise form?
The acinar cells
But the most common pancratic cancer is ductal carcinoma
This is due to acinar-ductal dysplasia where acinar cells become ductal cells
Acinar cell carcinoma histology
Neoplastic cells with oesonophilic granular cytoplasm
Positive immunoreactivity for lipase, trypsin, chymotrypsin
Dysplastic ductal lesions giving rise to ductal carcinoma
Pancreatic Intraductal Neoplasia
Intraductal Mucinous Papillary Neoplasm
K-ras mutations in 95% of cases
What is Trousseaur’s syndrome?
Migratory thrombophlebitis
Can be a sign of ductal pancreatic carcinoma
Electrolyte abnormality in ductal pancreatic carcinoma
Hypercalcamia
Ductal carcinoma microscopic appearance
Adenocarcinoma - mucin secreting glands set in desmoplastic stroma
Characteristic invasion of pancreatic carcinomas
Perineural invasion
Commonest site of ductal carcinoma
Head > body > tail
Tumours on the head present earlier
Commonest site of pancreatic endocrine tumours/ neuroendocrine tumours (e.g. islet cell tumour)
Tail > body > head
Commonest type of secretory pancreatic tumour
Insulinoma
Derived form b cells
Sx - Whipple’s triad
Glucose <50mg/dl
Symptoms + signs of hypoglycaemia
Relief of symptoms on glucose administration
Give some other examples of neuroendocrine tumours
Gastrinoma - Zollinger Ellison syndrome - high acid output = recurrent ulceration
VIPoma (diarrhoea)
Glucagonoma - necrolytic migrating erythema
What do neuroendocrine tumours stain with?
Stained with neuroendocrine markers e.g. chromogranin stain
Most neuroendocrine tumour are…
Non-secretory
Which MEN syndrome might pancreatic endocrine tumours be associated with?
MEN1
Pituitary
Parathyroid
Pancreatic endocrine tumours
MEN1 vs MEN2A vs MEN2B
MEN 1 - pituitary, parathyroid, pancreatic endocrine tumours
MEN2A - parathyroid, thyroid, phaeo
MEN2B - medullary thyroid, phaeo, neuromas, Marfanoid habitus
Types of gallstones
Cholesterol
- radio-Lucent — needs USS
- single
Pigement
- radio-opaque — XR
- mulitple
- conatin calcium salts of unconjugated bilirubin
Gallbladder cancer type and cause
Adenocarcinoma
90% associated with gallstones
What are Rokitansky Aschoff sinuses
Diverticula of the gallbladder
Cause by the gallbladder contracting against an obstruction
Feature of chronic cholecystitis (in chronic cholecystitis the gallbladder will be small and fibrosed)
