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