Carcinoid tumours

• Tumours of enterochromaffin (neural crest) origin
• Capable of producing 5-HT
• Common sites – appendix, ileum and rectum
• Can also occur in the GI tract, ovary, testes and bronchus

Symptoms and signs

• Initially few
• GI tumours can cause appendicitis, intussusception or obstruction
• Hepatic mets can cause RUQ pain
• 10% are part of MEN1
• 10% occur with other neuroendocrine tumours
• Can also produce;
  • Bradykinin
  • Substance P
  • VIP
  • Gastrin
  • Insulin
  • Glucagon

Carcinoid syndrome

• Occurs in 5% and implies that tumour has spread to the liver
• Symptoms and signs;
  • Bronchoconstriction
  • Paroxysmal flushing – especially in upper part of the body
  • Facial telangectasia
  • Diarrhoea
  • CCF – tricuspid incompetence and pulmonary stensosis from 5-HT induced fibrosis
  • Many CNS effects including enhanced ability to learn new stimulus-response associations

Carcinoid crisis

• When a tumour outgrows its blood supply or is handled too much during surgery mediators are released
• This can cause life threatening vasodilatation, tachycardia, hypotension, bronchoconstriction and hyperglycaemia
• It is treated with high dose octreotide, supportive measures and careful fluid balance

Diagnosis

• 24hr urine 5-hydroxyindolacetic acid (5HIAA)
• If liver mets are not found then find the primary

Treatment

• Octreotide is a somatostatin analogue – effects lessen over time
• Curative resectioning may be possible – tumours very yellow in appearance
• Octreotide cover is required during surgery to present a massive carcinoid crisis