CARCINOID TUMORS

Question 1

Overview (4)

Answer 1

1- From intestinal entero-chromaffin cells (serotonin producing kulchitsky cells)
2- Most common in the ileum
3- Malignant behavior correlates with lesion size
4- Carcinoid syndrome is a term used to describe the symptoms that arise as a result of serotonin (5-HT), bradykinin, histamine, and prostaglandin release into the circulation by the tumor (bypass metabolism in the liver and are released in systemic circulation due to metastasis in liver)

Question 2

Clinical Features (4)

Answer 2

1- Carcinoid tumor: obstruction (most common presentation), fatigue, weight loss
2- Carcinoid syndrome only happens if these patients have liver metastasis
3- With liver metastasis, the tumor products are able drain directly to the hepatic vein (without being metabolized in the liver)
4- From the hepatic vein then into the systemic circulation causing flushing, SOG, wheezing, diarrhea, abdominal pain, right sided cardiac valvular fibrosis (stenosis or regurgitation), left sided valves aren’t affected because the lungs have monamine oxidase —> metabolizes 5-HT before reaching left sided heart valves

Question 3

Investigations (3)

Answer 3

1- Carcinoid syndrome:
- Urinary levels of 5-hydroxyindoleacetic acid (5-HIAA) will be high (breakdown products of serotonin)
- Serum measurement of serotonin or chromogranin
2- Diagnosis of carcinoid tumor is made at laparotomy
3- Liver ultrasound confirms presence of metastasis

Question 4

Management (3)

Answer 4

1- Treatment is symptomatic
2- Inhibition of tumor products with:
- somatostatin analogues or octreotide or 5-HT antagonists (cyprohepatidine)
3- Reducing tumor mass through:
- surgical resection of primary tumor and liver secondaries if possible or hepatic artery embolization or radiofrequency ablation or chemotherapy