HistoPath - Liver Pathology Flashcards
(41 cards)
What is the blood supply of the liver
Dual: portal vein and hepatic artery
What cells are found in the liver (+ function of hepatocytes and bile ducts)
- Hepatocytes (Carries out the metabolic activity, have microvilli)
- Bile ducts (cholangiocytes) - Carries bile from hepatocytes to the duodenum
- Blood vessels (Portal vein, hepatic artery)
- Endothelial cells
- Kupffer cells
- Stellate cells
what is normal weight of the liver
1500g
Describe the structure of the liver and how blood flows through it
Portal vein → portal tract → central vein
Blood enters the portal tract, and the blood from the hepatic artery and portal vein mix, then diffuse down the sinusoids (Spaces between hepatocytes)
The blood will flow from the portal tract to the central vein
There are 3 zones with each having different functions
What makes up the portal tract
Hepatic artery (branch)
Portal vein (branch)
Bile duct
There is usually a ring of collagen around the portal triad - this is called the limiting plate
What does the ‘streaming river’ of the liver describe
They begin life in zone 1, grow up in zone 2 and retire in zone 3’
Therefore, cells in zone 3 have more metabolically active enzymes
Most alcoholic liver damage will be in zone 3
Most chronic hepatitis will occur in zone 1 (near portal vein)
What is the cellular mechanism during liver injury
- Hepatocytes lose microvilli
- Stellate cells are activated → myofibroblasts
- Endothelial cells become continuous/join together
- Collagen production into the space of Disse (where stellate cells sit)
This all means that blood does not interact with hepatocytes well
Define cirrhosis of the liver
The WHOLE liver is involved, where there is fibrosis, distortion of liver vascular architecture (intra- and extra-hepatic, e.g. gastro-oesophageal, shunting of blood), and nodules of regenerating hepatocytes
what types of shunts can be found in a cirrhotic liver
Extrahepatic shunt
Blood is bypassing the portal vein, liver and hepatic veins
E.g. oesophageal varices (blood is not coming back from the portal circulation into the systemic)
Intrahepatic shunt
Blood passes through the live, but straight from the portal vein to the hepatic vein (Bypassing hepatocytes) -> unfiltered blood
How is cirrhosis in the liver classified
a) according to nodule size: micronodular or macronodular
b) according to aetiology:
1) alcohol / insulin resistance (usually micronodular)
2) viral hepatitis etc. (usually macronodular, may be reversible)
What are the complications of liver cirrhosis
Portal hypertension
Hepatic encephalopathy
Liver cell cancer (Cirrhosis is the most important risk factor)
What is acute hepatitis and what are the causes
hepatitis <6 months
Viruses (hep A and E)
Drugs
What are the histological features of acute hepatitis
Spotty Necrosis (common in all types of acute hepatitis)
Lots of apoptosis
Lymphocyte and macrophages damage hepatocytes
What is chronic hepatitis and what are the causes
Hepatitis > 6 months
Viral hepatitis (Hep B,C,D)
Drugs
Auto-immune
What does grade and stage refer to in the context of chronic hepatitis
Grade = severity of inflammation
Stage = severity of fibrosis
What is the difference between portal inflammation, interface hepatitis, and lobular inflammation
Portal inflammation: inflammation limited to the portal tract, hepatocytes can be distinguished
Interface hepatitis: T cell mediated destruction of hepatocytes via apoptosis, inflammation crosses the limiting plate
Lobular inflammation: similar to acute hepatitis, spotty necrosis seen
What are the stages of liver disease
At the onset of a new disease, patients begin to develop fibrosis (F0-F3)
At F2-F3, there is shunting of blood
At F4, patients have developed compensated cirrhosis which can become:
Decompensated if the liver loses its mass → liver transplant needed
Hepatocellular carcinoma (HCC)
What are the 3 patterns of alcoholic liver disease
Fatty liver
Alcoholic (fatty liver) hepatitis
Cirrhosis
These patterns often co-exist
Describe fatty liver
Macroscopically: liver is pale and yellow (fat)
Microscopically: hepatocytes full of fat droplets
Can be reversible in alcoholics - when drinking cessation occurs, the fatty change reverses (but hepatitis will not)
What are the histological features of alcoholic hepatitis
Ballooning/swelling of cells
Mallory Denk/Mallory-Hyaline bodies - pink material that represents the collapsed cytoskeleton of hepatocytes
Hepatocyte apoptosis
Pericellular fibrosis (individual/groups of cells are marked by collagen)
Neutrophil polymorphs
The cells containing the most acetaldehyde dehydrogenase lie in Zone 3 - breakdown of acetaldehyde (toxic metabolite of alcohol) → hypoxic cells due to metabolic effort required
Describe the microscopic and macroscopic appearance of the liver in alcoholic cirrhosis
Micronodular cirrhosis - small uniform nodules seen
Pale with fatty change
What are the histological features of cirrhosis
Nodular regenerating hepatocytes surrounded by fibrosis
Fat droplets observable
Describe Non-Alcoholic Fatty Liver Disease (NAFLD) and its histological appearance
includes non-alcoholic steatohepatitis (NASH)
Due to insulin resistance (associated with BMI and DM)
Histology: looks like alcoholic liver disease
Describe primary biliary cholangitis (PBC) and its histological features (+marker)
Bile duct loss secondary to chronic inflammation (often with granulomatous inflammation from granuloma formation)
Granulomatous structure of bile ducts which are surrounded by epithelioid macrophages (↓)
Anti-mitochondrial antibodies (AMA)
