Symptoms:

• Brownish or bluish-gray pigmented spots on the lips, gums, inner lining of the mouth, and skin
• Clubbed fingers or toes
• Cramping pain in the belly area
• Dark freckles on and around the lips of a newborn
• Blood in the stool that can be seen with the naked eye (occasionally)
• Vomiting

Signs and tests:

A colonoscopy or flexible sigmoidoscopy shows intestinal polyps. The polyps develop most commonly in the small intestine, but also in the colon. An x-ray of the abdomen may also show polyps.

Additional exams may show:

• Intussusception (part of the intestine folds in on itself)
• Noncancerous tumors in the ear (exostoses)

Laboratory tests may include:

• Complete blood count -- may reveal anemia
• Genetic testing
• Stool guaiac
• Total iron-binding capacity (TIBC)