somatostatinoma

Last reviewed 01/2018

Somatostatinomas:

• very uncommon islet cell tumours
• the majority (more than 60%) are large tumours (mean diameter 5 cm) located in the head and body of the pancreas
• other sites for insulinomas are in the periampullary region of the duodenum and in the small intestine
  • these tumours are generally smaller

Characteristically pancreatic somatostatinomas present with a triad of gallstones, steatorrhoea and diabetes mellitus. The plasma immunoreactive levels are usually increased to more than 10 times normal levels.

Extrapancreatic somatostatinomas can present in association with neurofibromatosis type I and phaeochromocytoma

Presenting features of extrapancreatic somatostatinomas include:

• obstructive pancreatitis
• obstructive jaundice
• small intestinal haemorrhage
• small intestinal obstruction
• abdominal pain

Localization of somatostatinoma:

• pancreatic somatostatinomas and metastases - detected with transabdominal ultrasonography and CT scanning
• duodenal somatostatinomas - generally found during endoscopy

Management:

• seek specialist advice
• pancreatic somatostatinomas (because of their large size) - only rarely can be cured by extensive surgery - often a Whipple's procedure often has to be performed
  • cytoreductive debulking surgery may result in palliation
  • prognosis ranges from weeks to years
• duodenal somatostatinomas may be treated with surgery alone, although again a Whipple's procedure often has to be performed
• hepatic embolization - used for the palliation of metastatic disease

Reference:

1. de Herder WW and Lamberts SWJ. Best Practice & Research Clinical Endocrinology & Metabolism; Volume 2004 18(4): 477-495.