Somatostatinoma

 

Clinical Background

Somatostatinomas are pancreatic neuroendocrine tumors that produce excessive amounts of somatostatin and are located either in the duodenum or pancreas.

Epidemiology

  • Incidence – <1/1,000,000
  • Age – median is 40s
  • Sex – M:F, equal
  • Occurrence – usually sporadic

Risk Factors

  • Genetic
    • Small percentage associated with multiple endocrine neoplasias type 1 (MEN1)
    • Also may be associated with Von Recklinghausen disease (type 1 neurofibromatosis)

Pathophysiology

  • Locations for tumor – duodenum or pancreas
  • Hormone secretion is somatostatin
    • Inhibits the release of many hormones (gut hormones including insulin, pancreatic polypeptide, glucagon, gastrin, secretin, glucose-dependent insulinotropic peptide and motilin)
    • Neurotransmitter function
  • Significant number of these tumors are metastatic

Clinical Presentation

  • Somatostatinoma syndrome
    • Diabetes mellitus – occurs in about 10%
    • Cholelithiasis
    • Diarrhea/steatorrhea
  • Tumor may be found incidentally if not associated with the syndrome (patient will be asymptomatic)
  • Metastatic disease is frequently found at the time of diagnosis

Treatment

  • Symptomatic relief
  • Somatostatin analogues
  • Resection