Carcinoid syndrome

W hat is Carcinoid syndrome?

Carcinoid syndrome is a possible complication of gastroenteropancreatic neuroendocrine tumours (GEP-NETs) if they spread to the liver.

Carcinoid syndrome is a set of symptoms that can sometimes develop if:1

a) you have a GEP-NET that has spread (metastasised) to the liver AND
b) it is producing too much of the hormone serotonin

About 1 in 10 people with GEP-NETs develop carcinoid syndrome.2
The main symptoms of carcinoid syndrome are:2,3

  • Hot, red flushing of the skin
  • Diarrhoea

Other symptoms of carcinoid syndrome are shown here:2,4


  1. NHS. Carcinoid syndrome. Available at: Last accessed September 2020.
  2. NORD. Carcinoid syndrome. Available at: Last accessed October 2020.