Somatostatinomas Clinical Presentation

Updated: Jun 29, 2015
  • Author: Praveen K Roy, MD, AGAF; Chief Editor: Julian Katz, MD  more...
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Presentation

History

Most patients with somatostatinomas are symptomatic. Because tumors are slow growing and symptoms are often present for several years before diagnosis, the disease is often quite advanced by the time patients obtain appropriate medical attention.

Two different symptomatic presentations can be distinguished. The inhibitory syndrome is common in pancreatic somatostatinomas, whereas tumors arising from the duodenal wall are more likely to manifest in association with mechanical enteric obstructive symptoms. Duodenal somatostatinomas may secrete reduced amounts of hormone that are insufficient to produce a systemic effect.

The classic clinical pentad of somatostatinoma syndrome is as follows:

  • Diabetes mellitus: Symptoms range from mild glucose intolerance to frank hyperglycemic ketoacidosis.
  • Cholelithiasis: Patients typically present with symptoms of biliary colic or other complications of gallstones.
  • Weight loss: Patients may lose 18-45 lb. This symptom is more common with pancreatic tumors.
  • Steatorrhea and diarrhea: Patients characteristically report 3-10 exceptionally malodorous stools per day.
  • Hypochlorhydria and achlorhydria: This is generally an asymptomatic condition resulting from somatostatin-mediated inhibition of gastric acid secretion.

Hypoglycemia, abdominal pain, anorexia, nausea, and vomiting are also relatively common complaints. Patients with duodenal somatostatinomas can present with obstructive jaundice, duodenal obstruction, abdominal pain, or gastrointestinal bleeding.

Mixed clinical syndromes can occur if multiple functional hormone products are secreted in sufficient amounts. Patients with such tumors do not present with a predictable clinical pattern; instead, they exhibit a range of clinical and biochemical features of different types of pancreatic endocrine neoplasms.

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Physical

Physical examination findings help identify patients with neurofibromatosis in association with somatostatinoma. As previously discussed, patients with somatostatinoma usually have weight loss and may develop jaundice if biliary tract obstruction is present. Physical findings are otherwise nonspecific.

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Causes

Somatostatinoma is associated with multiple endocrine neoplasia type 1 (MEN 1) syndrome in 7% of cases. Duodenal somatostatinomas are occasionally associated with neurofibromatosis and pheochromocytoma.

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