Endocrine Pancreas - Pathology

()Map ENDOCRINE SYSTEM (Map) PANCREAS PATHOLOGY

Anatomy and Physiology

Anatomy and Physiology of the pancreas can be found here.

Degenerative pathology

Aetiology

• Hypoplasia of panceatic islets where exocrine cells are functional
• Degeneration of the islet cells occurs in acute pancreatic necrosis along with acinar tissue necrosis, atrophy occurs during chronic interstitial pancreatitis
• Extensive neoplastic destruction may also contribute to islet loss
• Causes Diabetes mellitus (DM)
• In cats
  • Amyloidosis of the islets is sometimes observed and may be restricted to just them
    • May result in signs of DM or have no symptoms
    • Hydropic (vacuolar) degeneration of beta cells
    • Acumultion of glycogen within the cytoplasm
    • Develops in response to long-term overstimulation due to peripheral insulin resistance
• In dogs
  • Sclerosis of the islets is sometimes observed in dogs with DM without pancreatic necrosis but also in dogs without DM

For degeneration of exocrine tissue see 'degenerative disease of exocrine pancreas in Alimentary section'

Neoplasia

Islet cell tumour (Image sourced from Bristol Biomed Image Archive with permission)

Insulin secreting neoplasms

• Adenomas and carcinomas deerived from beta cells
• Respond rapidly to iv glucose
• Can be identified by immunocytochemical means
• Dogs 5-12 years of age most commonly affected
• Older cattle, associated with periodic convulsions

Clinical signs

• Hyperinsulinism
• Hypoglycaemia - often episodic
  • Neurologic signs - stupor, confusion, coma, seizures, peripheral neuropathy may also develop

Adenomas (insulinomas)

• Usually single, or less often multiple, small (1-3cm) spherical nodule, yellow to dark red, in one or more lobes
• Thin layer of fibrous tissue separates normal parenchyma
• Small islets of acinar tissue are sometimes present within the neoplasm
• Well differentiated cells

Carcinomas

• Larger than adenomas
• Multilobular
• Invasive into parenchyma and surrounding tissue
• Metastasis into lymph nodes, liver mesentery, omentum
• Few mitotic figures

Gastrinoma

Image of pancreatic garstrinoma in a dog by Professor J.King

• Described in dogs, cats
• Known as Zollinger-Ellison syndrome in humans
• Uncommon compared to beta cell neoplasms
• Excess gastrin causes hyperacidity in the stomach and mucosal hyperplasia of the antral region causing gastric and duodenal ulceration

Clinical signs

• Anorexia
• Severe weight loss
• Vomiting
• Diarrhoea
• Dehydration

Pathology

• Multiple variably sized neoplasms
• Increased connective tissue mass - firm
• Partiallty encapsulated
• Invade locally
• Metastases to liver and local lymph nodes are common

Glucagonoma

• Very rare
• Characterised by
  • Hyperglycaemia
  • Vacuolar hepatopathy
  • Skin erythema with superficial necrotising dermatitis
• Diagnosis in dogs is difficult as presents together with DM

For hyperplastic and neoplastic disease of exocrine pancreas see 'hyperplastic and neoplastic disease of exocrine pancreas in Alimentary section'