Does a Normal Colonoscopy at Age 9 Exclude Peutz-Jeghers Syndrome or Jejunal Hamartomatous Polyps?
No, a normal colonoscopy at age 9 does not exclude Peutz-Jeghers syndrome (PJS) or jejunal hamartomatous polyps, because the small bowel—particularly the jejunum and ileum—is the most common site for PJS polyps, and colonoscopy does not visualize these areas. 1
Why Colonoscopy Alone Is Insufficient
Small Bowel Is the Primary Site of PJS Polyps
- The jejunoileum is the most frequent location for hamartomatous polyps in PJS, not the colon. 2
- Jejunal polyps were detected in 72% of patients and ileal polyps in 55% of patients undergoing capsule endoscopy surveillance, demonstrating that small bowel involvement is the predominant feature. 3
- A normal colonoscopy only evaluates the colon and terminal ileum (if reached), leaving the vast majority of the small bowel unexamined. 1
Recommended Surveillance Protocol for PJS
- British Society of Gastroenterology guidelines recommend that GI surveillance in asymptomatic PJS patients commence at age 8 years with upper GI endoscopy, colonoscopy, AND video capsule endoscopy (VCE). 1
- If baseline colonoscopy and upper endoscopy are normal at age 8, they can be safely deferred until age 18 years; however, small bowel surveillance with VCE should continue every 3 years regardless. 1
- This guideline structure explicitly acknowledges that colonic findings do not predict small bowel disease burden. 1
Critical Clinical Implications
Risk of Intussusception
- Small bowel polyps causing intussusception is the major clinical problem in children with PJS, with a cumulative risk of 50-68% during childhood. 1
- 15-30% of PJS patients require surgery before age 10 years, with a median age of first intussusception of 10-16 years. 1
- Small bowel polyps greater than 1.5-2 cm should be considered for elective resection to prevent intussusception, even if asymptomatic. 1
Polyp Development Over Time
- Polyps require time for development and may not be present at initial screening, as evidenced by case reports of PJS diagnosed at age 3 years with subsequent polyp development. 4
- Early onset PJS presenting with polyps is quite rare since they require time for development, usually manifesting after the first decade of life. 4
What Should Be Done Instead
Complete Small Bowel Evaluation
- Video capsule endoscopy (VCE) is the recommended modality for small bowel surveillance in PJS, as it has similar accuracy to MRI enterography in detecting clinically significant polyps (>1 cm) and avoids repeated ionizing radiation. 1
- MRI enterography is complementary to VCE: while VCE may be better at detecting smaller polyps, MRI enterography is superior for localization and accurate sizing. 1
- Double balloon enteroscopy (DBE) should not be used as a surveillance tool but is reserved for therapeutic polypectomy when polyps are identified. 1
Diagnostic Confirmation
- PJS diagnosis requires any one of the following: two or more histologically confirmed PJ polyps, characteristic mucocutaneous pigmentation with family history, or STK11/LKB1 gene mutation. 1
- Look for hyperpigmented macules on the lips and oral mucosa (present in 93% of cases), which may fade with age but are pathognomonic when present. 1, 4, 2
- Obtain detailed family history, as 50% of cases have positive family history and the condition follows autosomal dominant inheritance. 2
Common Pitfalls to Avoid
- Do not assume a normal colonoscopy rules out PJS—the small bowel must be evaluated with VCE or MRI enterography. 1
- Do not delay small bowel surveillance beyond age 8 years in suspected or confirmed PJS, as intussusception risk peaks in childhood. 1
- Do not rely solely on colonoscopy findings to determine surveillance intervals—small bowel surveillance should continue every 3 years regardless of colonic findings. 1
- Investigate earlier if symptomatic (abdominal pain, bleeding, anemia, obstruction), as symptoms may indicate polyp-related complications requiring urgent intervention. 1, 4, 5