Pancreas and Gall Bladder Flashcards
Recall the normal anatomy of the pancreas
- Endocrine (Islet of Langerhans) and exocrine (acini) sections.
- Exocrine secretions go via different ducts (intercalated, interlobular, main pancreatic, common bile) to enter duodenum
What are the main causes of acute pancreatitis?
- Duct blockage –> 50% caused by Gallstotnes (+trama and tumours)
- Metabolic/toxic –> alcohol (2nd most common cause, 1/3) 5% of alcoholics will get acute pancreatiti, + drugs, hypercalcaemia and hyperlipidaemia
- ischaemic
- Infection/inflammation viruses (mumps)
- autoimmune - IgG4
- Idiopathic 15%
How does duct obstruction cause acute pancreatitis?
Reflux of bile followed by damage to acini activates pancreatic pro-enzymes –> damage to acini –> more release of pancreatic pro-enzymes
How doe alcohol cause acute pancreatitis?
Alcohol leads to spasm/oedema of Sphincter of Oddi and the formation of a protein rich pancreatic fluid which obstructs the pancreatic ducts
What is the pattern of inflammation in acute pancreatitis with alcohol or gall-stones?
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
- Release of enyzmes cause acinar necrosis –> oedema / haemorrhagig necrosis
- FAT NECROSIS (due to release of lipase binding to calcium)
What histological features indicate acute pancreatitis?
- stromal oedema - haemorrhagic necroris
2.Fat necrosis (lipases bind go calcium) (blue areas)
What are the local and systemic complication sof acute pancreatitis?
Local complications:
- pseudocyst, abscess
Systemic
- shock
- hypoglycaemia
- hypocalcaemia (due to fat necrosis formation but can appear normocalcaemia if hypercalaemia was cause of pancreatitis in the first place)
What is the prognosis of an episode of acute pancreatitis?
Up to 50% mortalitiy in haemorrhagic pancreatitis
What are the main causes of chornic pancreatitis?
Alcohol 80%
Haemochromatosis
+ Duct obstructions (potentially gallstones, abnormal pancreatic duct anatomy
+ or cystic fibrosis
Idiobpathic
What are the histological changes seen in chronic pancreatitis?
- chornic inflammation –> lymphocytes with parenchymal fibrosis (hallmark) and loss of parenchyma (usually of acini, less of ilslands) , might be calcified (vs acute fat necrosis)
- Duct structures with calcified stones with secondary dilatations
Picture–> show fibrosis and islands of langerhans (might look like neuro-endocrine tumour)
What is a pancreatic pseudo cyst?
What is their aetiology, definition, and complications?
Can be formed b y acute or chronic pancreatitis
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 (if perforation –> rlease of pancreatic enzymes, dangerous)
What is IgG4 related pancreatitis?
Autoimmune pancreatitis
IgG4 related diseas is a disease in of itself causing inflammation pretty much anywhere in the body
Characterised by large numbers of IgG4 positive plasma cells
What is the most common pancreatic cancer?
What other malginancies can arise=?
Most: ductal caricinoma (small % acini carcinom)
Other possible, more rare:
- Cystic neoplasm (serous + mucinous)
- Pancreatic neuroendocrine tumours (islet cell)
What is the pre-malignant stage of ductal carinomas of the pancrease?
What is the main genetic mutation driving it?
Usually 2
1. PanIN (pancreatic intraductal neoplasia)
2. Intrductal Mucinous Papillary Neoplasm
95% have K-ras mutation
What is the main macroscopic and microscopic appearance of ductal carcinomas in the pancreas?
- Macroscopic: Gritty and grey
Invades adjacent structures
Tumours in the head present earlier
Microscopic
Adenocarcinomas:
mucin secreting glands set in desmoplastic stroma