
Overview of Neuroendocrine Tumors
A panelist discusses how neuroendocrine tumors are defined by World Health Organization (WHO) classification, graded based on Ki-67 proliferative index, diagnosed through imaging (often incidentally), and most commonly found in the small bowel, lungs, and pancreas.
Video content above is prompted by the following:
Definition, Classification, and Diagnosis of Neuroendocrine Tumors
Panel Introduction
Expert Panelist:
- Thorvardur R. Halfdanarson, MD - Professor of Oncology and Medical Oncologist at Mayo Clinic, Rochester, Minnesota
Key Themes:
- WHO Classification System:
- Neuroendocrine tumors are classified according to the WHO system by grade (1, 2, and 3)
- Classification based on Ki-67 proliferative index: grade 1 (<3%), grade 2 (3%-20%), grade 3 (>20%)
- Grade 3 has 2 subtypes: well-differentiated neuroendocrine tumors and poorly differentiated neuroendocrine carcinoma
- Diagnostic Methods:
- Most commonly diagnosed through imaging
- Many well-differentiated tumors are discovered incidentally during imaging for unrelated conditions
- Some present with functional syndromes (eg, carcinoid syndrome with flushing and diarrhea)
- Common Locations:
- 70% to 80% occur in the small bowel, lungs, and pancreas
- Can occur throughout the gastrointestinal tract from esophagus to rectum
- Some extraintestinal, extrathoracic locations include larynx, gallbladder, and gynecologic organs
Notable Insights:
Dr. Halfdanarson noted an increasing trend of incidental discovery, sharing a recent case where a patient being treated for kidney stones was found to have a pancreatic neuroendocrine tumor.







































