Symptoms:

Most carcinoid tumors have no symptoms. They only produce the syndrome about 10% of the time.

When symptoms do occur, they may include:

• Abdominal pain that comes and goes
• Bright red flushing of the face
• Diarrhea (may be explosive and severe)
• Heart palpitations
• Low blood pressure
• Wheezing

Sometimes symptoms are brought on by physical exertion, or eating or drinking things such as blue cheeses, chocolate, or red wine.

Signs and tests:

Most of these tumors are found during abdominal surgery.

A physical examination may show:

• Heart valve lesions
• Signs of niacin-deficiency disease (pellagra)

Tests may include:

• 5-HIAA levels in urine
• Blood tests (including serotonin blood test)
• CT and MRI scan
• OctreoScan (to identify most carcinoids and other neuroendocrine tumors)