Table 1. Sites of NETs, Associated Symptoms, and Secreted Hormones.

Hormone	Common location	Tumor	Key symptoms
Serotonin	Small intestine, stomach, pancreas, duodenum, colon, appendix rectum	NET (carcinoid)	Diarrhea, cutaneous flushing, bronchospasm, valvular heart disease
Insulin	Pancreas	Insulinoma	Hypoglycemia, confusion, loss of consciousness, sweating or dizziness, weight increase
Gastrin	Duodenum, pancreas	Gastrinoma	Acid reflux, abdominal pain, diarrhea, fat malabsorption
Glucagon	Pancreas	Glucagonoma	Diabetes mellitus, skin lesions (necrolytic migratory erythema), glossitis, anemia, weight loss, venous thrombosis
VIP	Pancreas	VIPoma	Diarrhea, hypokalemia, metabolic acidosis
ACTH	Lung, adrenals, thyroid, pancreas	ACTHoma	Muscle weakness, hypokalemia, weight changes, truncal obesity, hypertension, diabetes
PTH	Lung, pancreas	PTH-like-oma	Hypercalcemia
Somatostatin	Pancreas, duodenum	Somatostatinoma	Abdominal pain, jaundice, gastrointestinal bleeding, gallstones, diarrhea, diabetes, weight loss, hypochlorhydria

Note. NET = neuroendocrine tumor; ACTH = adrenocorticotropic hormone; PTH = parathyroid hormone; VIP = vasoactive intestinal peptide. Information from Camilleri (2015); Sandhu & Jialal (2018); Vinik et al. (2010); Zandee et al. (2017).