Liver & biliary system pathology 1

What is being shown here?

• Absence of liver lobe (aplasia of the left lobe)

  • Not likely to have clinical sings

• Can also get supernumerary lobes

What congenital defect is being shown here?

• Bovine, aborted fetus, liver: congenital cysts

• If calf had been born liver function may have been compromised

What is being shown here?

• Polycystic kidney syndrome

• Inherited disease (autosomal dominant)

What are the different congenital portosystemic vascular shunts?

What breed of dog are each of them seen in?

How do you treat them?

• Intrahepatic shunt: due to persistence of fetal ductus venosus (large breed dogs)

  

• extrahepatic shunt:due to direct connections between portal vein and vena cava / azygous vein (small breed dogs and cats)

  

• can treat surgically

What is the ductus venosus?

Fetal connection between left umbilical vein (portal vein) and caudal vena cava

What will be seen grossly and histologically with congenital portosystemic vascular shunts?

gross

• small liver

histology

• small hepatocytes

• small / absent portal veins in triads

• reduplication of arterioles in triads

Describe what is being shown here?

• Liver is small in relation to the stomach

• Pale due to lack of blood supply

What is being shown here?

• Diaphragmatic hernia

• Common in cats following RTA

What is being show here?

Which lobe is most predisposed to this?

• Torsion of one liver lobe

• Occludes the blood supply and the lobe becomes necrotic

• Left lateral lobe is predisposed (most mobile), but torsion is rare.

• Haemorrhagic shock > death

What is being shown here and what causes it?

• Rupture

• blunt trauma (e.g. road traffic accidents)

• alterations in parenchyma (e.g. amyloidosis - shown in image, lipidosis) - more friable

• neoplasms (e.g. haemangiosarcoma)

What does acute congestion in the liver cause?

• Pressure will spread from the hepatic lobule to the portal area

• Acute cardiovascular failure (i.e. agonal)

• Anaphylaxis

• Shock

What occurs with chronic congestion?

• Increased venous pressure (due to red CO)

• Ascites

• Hydrothroax

What is seen grossly with nutmeg liver?

• slightly nodular and rough surface(irregular outlines of the liver)

• ascites, fibrin deposition

• pooling of blood (due to congetsion)

  

What will be seen histologically with nutmeg liver?

• centrolobular necrosis

• fibrosis around central vein

Describe how acquired extrahepatic porto-systemic shunts occur?

• hepatic fibrosis and/or cirrhosis

• development of portal hypertension

• dilation of (non-functional) veins between portal vein (or veins which terminate in the portal vein) and caudal vena cava

What is being shown here?

• Dilated tortuous blood vessels

• Can't treat surgically due to multiple vessels and underlying liver issue

What is being shown here and what species is it usually in?

• Teleangiectasis = dilation of functional blood vessels (not clinically releavant)

• Cattle and cats

What is being shown here and what species is it in?

• peliosis hepatis = irregular blood-filled cystic spaces in the liver parenchyma

• mainly in cats

What is being shown here?

• Degeneration of hepatocytes

• “Cloudy swelling” or hydropic (water) degeneration

What causes hepatocyte degeneration?

• Non-specific change (e.g. toxins, metabolic insults, hypoxia, cholestasis)

• Reversible

What causes atrophy of hepatocytes?

• pressure from other internal organs

  • Chronically distended right dorsal colon (same can occur with distended rumen)

    

• reduced blood supply (e.g. shunt)

What are the different types of lipidosis of the liver?

• Nutritional lipidosis

  • excessive release of free fatty acids from adipose tissue (peak lactation and parturition)

• Hypoxic lipidosis

• Toxic lipidosis

What clinical scenarios would pre-dispose different species to hepatic lipidosis?

• Peak lactation in cattle

• Twin lamb disease in sheep

• Obese pony that gets muzzled (sudden change in diet)

• Onset of colic - sudden decrease in eating/ feed restriction

• Cat being stuck somewhere

What is being shown here?

• Lipidotic liver

• Large - rounded edges to the lobes

• Yellow

• Friable

What is being shown in this liver with lipidosis?

How do you confirm it is lipidosis?

• Large clear vaculoses

• Nucleus to the side (dif to degeneration)

• Oil Red O stain

What can cause hyperlipidaemia?

• with diabetes mellitus, pancreatitis, hypothyroidism, hyperadrenocorticism

• with high dietary fat intake

• equine hyperlipidaemia, feline idiopathic hepatic lipidosis

What causes ketosis?

• with starvation, diabetes mellitus, pregnancy, lactation

• Sheep; pregnancy toxaemia “twin lamb disease”

What is Hypoglycaemia and fatty liver syndrome seen with?

• Small dog breeds

• Low capacity for gluconeogenesis from muscle protein as small muscle mass; anorexia due to stress (infection, vaccination)

What can excess glucocorticoids cause in the body?

• Decreased lipogenesis

• Increased lipolysis of adipose tissue

• Increased catabolism of skeletal muscle protein

• Increased gluconeogenesis in the liver (↑ glycogen stores)

What is being shown here?

• Focal lipidosis due to tension from the ligament

• Incidental finding

When would glycogen accumulate in the liver?

• Abnormal glucose or glycogen metabolism

• Diabetes mellitus

• Glycogen storage diseases (genetic)

• Steroid-induced hepatopathy (dogs)

  • exogenous/iatrogenic

  • Cushing’s disease (hyperadrenocorticism)

How would we confirm it is glycogen on histology?

PAS stain

Where is amyloid usually deposited?

Between cells (in space of Dissé and sinusoids)

What type of amyloid will be deposited?

• Usually AA (amyloid-associated):

• Synthesised in hepatocytes

• Usually systemic (generalised): deposition in several organs

What is being shown here?

• Diffuse amyloidosis and ruptures

• Pale orange/tan, enlarged, rounded edges

What is being shown here?

• Amyloidosis

• Accumulation of eosinophilic material BETWEEN cells

What is being shown here?

• Hepatic melanosis

• Not clinically significant

What is Haemochromatosis?

Hepatic haemosiderin accumulation due to increased iron uptake

What stain would you use to identify iron?

Perl’s Prussian blue stain

What is photosensitisation caused by?

• Defective pigment synthesis

• Intoxication

  • St. John`s wort (Hypericum perforatum)

  • Buckwheat (Fagopyrum spp.)

  • Spring parsley (Cymopterus watsoni)

What are the clinical signs associated with defective pigement synthesis?

• Reddish-brown pigment deposition in dentin and bone (pink teeth) and liver, excretion with urine

• Skin lesions develop because uroporphyrins absorb UV-A radiation reactive O2 species