Pancreas Pathology

Pancreas Pathology

1. Exocrine

   • Digestive
   • Proteolytic enzyme content can damage adjacent tissues
   • Structure
     • Lobules of exocrine pancreatic acini, separated by fine fibrous trabeculae
     • Cat
       • One major pancreatic duct which shares a common entry into the duodenum with the common bile duct
     • Dog
       • May be several major pancreatic ducts
         • No common entry w/ the bile duct
   • Developmental Conditions
     • Pancreatic Acinar Atrophy
       • Dogs
         • Juvenile onset
         • German Shepherds: Autosomal recessive inheritance
         • Rough coated collies & English setters: Familial disease
       • Likely autoimmune (Large #'s of lymphocytes & plasma cells targeting exocrine pancreas => Fibrosis)
       • Islets of Langerhans are normal
       • Most common cause of Exocrine pancreatic insufficiency (EPI) - Dogs
       • Clinical signs by 6-12 months of age
   • Acquired Conditions
     • Exocrine pancreatic insufficiency
       • Fatty diarrhoea (steatorrhoea)
         • Insufficient lipase => undigested fat in diarrhoea => malabsorption sydrome
       • Weight loss (Cachexia)
       • Voracious appetite
       • Pica, Coprophagia
       • Concurrent small intestine bacterial overgrowth (SIBO)
     • Pancreatic calculi (Pancreolithiasis)
       • Uncommon
       • Incidental PM finding (Cattle)
   • Interstitial Pancreatitis
     • Acute
       • Cats
         • Systemic toxoplasmosis
     • Chronic
       • Cats
         • Often concurrent w/ Cholangitis & Enteritis (Triaditis)
       • Extension of process that commences in the ducts
         • Usually ascending infection of intestinal bacteria
         • Also, migrating parasites
       • Horses
       • Histologically
         • Hyperplasia of pancreatic ducts & periductular fibrosis & inflammation
       • Can lead to exocrine pancreatic insufficiency/diabetes mellitus
   • Necrotising Pancreatitis
     • Acute Pancreatic Necrosis
       • Imp. in Dog (Small breeds)
       • Less common in Cats
       • Activation of Trypsinogen => Trypsin w/in the pancreas => activation of cascade of pancreatic proenzymes leading to autodigestion & tissue damage
         • Occurs due to fusion of zymogen granules with lysosomes
         • Release of pancreatic enzymes into circulation => Hepatic necrosis, Pulmonary oedema, Interstitial pneumonia, Myocardial injury (& arrhythmias), Shock & DIC
         • Dystrophic mineralization of necrotic abdominal fat (saponification)
       • Necrosis of the pancreas, adjacent connective tissues & abdominal fat
       • Blood vessels also involved => Haemorrhage, thrombosis, ischaemia
       • Sequelae:
         • Complete resolution (fibrosis & nodular regeneration)
           • Chronic relapsing "smouldering" pancreatitis => Eventual complete loss
             • Diabetes Mellitus (Destruction of Islets)
   • Nodular Hyperplasia
     • Common in older animals
     • Multiple nodules
       • Raised, smooth, grey or white
       • Non-functional
     • Often mistaken for Neoplasia
   • Neoplasia
     • Exocrine Adenomas
       • Rare, Solitary
     • Exocrine Carcinomas
       • Dog & Cat
       • Single or multiple/confluent, firm, white or pale yellow nodules
       • Non-functional
       • Aggressive
         • Invade adjacent tissues & pertoneum
           • Metastasize to liver
             • Obstruct bile flow => Jaundice

2. Endocrine

   • Metabolic
   • Structure
     • Islets of Langerhans (Small foci b/w acini)
       • Alpha, beta, gamma, PP(F) & other cells

3. Pancreatic Disease:

   • Alimentary tract signs: Maldigestion
     • Concurrent biliary duct obstruction
       • Jaundice (Cats - Triaditis)
       • Metabolic Disease
         • Endocrine pancreas

Images and files in the map