Gastroenterologist Dr David Metz Shares His Insights on the Presentation and Diagnosis of Neuroendocrine Tumors (NET)

"The Variable Presentation of NET"

"The bottom line is that all neuroendocrine tumor patients are somewhat unique in that they present in very varied ways, and because of the subtle symptoms that are very varied, they also are often misdiagnosed for many, many years, and labeled as having other conditions that are far more common."

— Dr David Metz

Common NET symptoms

Subtle differences between the symptoms of carcinoid tumors and other conditions can make diagnosis easier.

  • Nocturnal diarrhea is characteristic of carcinoid syndrome1,2
  • Flushing associated with carcinoid syndrome is intermittent and generally not accompanied by sweating (dry flushing)3

For more information, see Clinical presentation of NET.

"Tools for Making the Diagnosis"

"So how does one actually make a diagnosis in these patients? Itís difficult because the presentation is so varied. Some patients present with flagrant syndromic presentations. Others will present later, such as small-bowel carcinoid syndrome patients, who may present with widely metastatic disease and a syndromic presentation."

— Dr David Metz


Biochemical testing is key to confirming a diagnosis3,4

  • Chromogranin A (CgA) and 5-HIAA testing can both be used to diagnose carcinoid tumors

Dr David Metz

Dr David Metz

Associate Chief of Clinical Affairs, Division of Gastroenterology

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  1. Jensen RT, Doherty GM. Carcinoid tumors and the carcinoid syndrome. In: DeVita VT Jr, Hellman S, Rosenberg SA, eds. Cancer: Principles & Practice of Oncology. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2004:1559–1574.
  2. Wiedenmann B, Pape U–F. From basic to clinical research in gastroenteropancreatic neuroendocrine tumor disease—the clinician–scientist perspective. Neuroendocrinology. 2004;80(suppl 1):94–98.
  3. Vinik AI, Woltering EA, Warner RRP, et al. NANETS consensus guidelines for the diagnosis of neuroendocrine tumor. Pancreas. 2010;39(6):713–734.
  4. Zuetenhorst JM, Taal BG. Metastatic carcinoid tumors: a clinical review. Oncologist. 2005;10(2):123–131.