Endocrine Pancreas - Pathology

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 from Cornell Veterinary Medicine

• 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