What is Peutz‑Jeghers syndrome and should it be considered in a 19‑year‑old male presenting with jejunal intussusception?

Peutz-Jeghers Syndrome and Jejunal Intussusception in Young Adults

Peutz-Jeghers syndrome (PJS) should absolutely be considered in this 19-year-old male with jejunal intussusception, as intussusception is the most common acute complication of PJS in young patients, occurring in 50% of cases by age 20 years. 1

What is Peutz-Jeghers Syndrome?

PJS is an autosomal dominant genetic disorder caused by germline mutations in the STK11/LKB1 gene, characterized by hamartomatous polyps throughout the gastrointestinal tract and distinctive mucocutaneous melanin pigmentation. 1

Key Diagnostic Features

The diagnosis can be established with any ONE of the following criteria: 1

• Hamartomatous polyp(s) PLUS at least 2 of: labial melanin deposits, family history of PJS, or small bowel polyposis 1
• Two or more PJS polyps 1
• Any number of PJS polyps with a family history of PJS in a close relative 1
• Characteristic mucocutaneous pigmentation with family history 1

Distinctive Clinical Characteristics

Mucocutaneous pigmentation (present in >95% of patients): 1

• Dark brown or blue-brown macules, 1-5 mm in size 1
• Located on vermilion border of lips (94%), buccal mucosa (66%), hands (74%), feet (62%) 1
• Critical pitfall: Pigmentation typically appears in infancy but fades in late adolescence and adulthood, so absence in a 19-year-old does NOT exclude PJS 1
• Unlike common freckles, PJS pigmentation crosses the vermilion border and appears on buccal mucosa 1

Hamartomatous polyps: 1

• Distinctive histology with branching smooth muscle extending into the polyp, arborizing pattern, cystic gland dilatation, and normal overlying epithelium 1
• Most commonly found in small bowel and colon 1
• Can appear anywhere in the GI tract except esophagus 2

Why This Matters for Your 19-Year-Old Patient

Intussusception is THE hallmark acute complication of PJS in young patients: 1

• Occurs in 15% of patients by age 10 years 1
• Occurs in 50% of patients by age 20 years 1
• Caused by hamartomatous polyps serving as lead points 3, 4
• Can be life-threatening, causing bleeding, obstruction, or bowel infarction 1

Critical diagnostic consideration: 4, 5

• Multiple intussusceptions can occur simultaneously in PJS patients 4, 5
• The entire small bowel must be examined intraoperatively to exclude additional intussusceptions 5

Immediate Clinical Actions

During surgical intervention for intussusception: 5

• Examine the ENTIRE small bowel for additional intussusceptions 5
• Send resected specimen for histopathology to identify hamartomatous polyp features 3
• Look for characteristic histologic features: hamartomatous architecture, arborizing smooth muscle, cystic glands 1

Post-operative evaluation to confirm PJS diagnosis: 1

• Perform detailed physical examination for mucocutaneous pigmentation on lips, buccal mucosa, hands, feet, perianal region 1
• Obtain detailed family history for PJS, early-onset cancers, or similar pigmentation 1
• Arrange genetic testing for STK11/LKB1 mutations (detected in 66-94% of PJS cases) 1
• Schedule upper and lower endoscopy to identify additional polyps throughout GI tract 3

Long-Term Cancer Surveillance Requirements

PJS patients face dramatically elevated cancer risks that mandate lifelong surveillance: 1

• Cumulative cancer risk: 1-2% by age 20, >30% by age 50, >80% by age 70 1
• Gastrointestinal cancers: Colorectal, pancreatic, stomach, small intestine 1
• Breast cancer: Significantly elevated risk requiring early screening 1
• Gynecologic cancers: Ovarian sex cord tumors with annular tubules (SCTAT), mucinous ovarian tumors, cervical adenocarcinoma 1
• Testicular tumors: Large-cell calcifying Sertoli cell tumors (LCCSCT) 1

Surveillance protocol starting immediately: 1

• Colonoscopy with polypectomy every 2 years 1
• Upper GI endoscopy every 1-3 years starting at age 18 1
• Annual pelvic examination and Pap test (for females) starting at ages 18-20 1
• Annual pelvic ultrasound (for females) 1
• Testicular examination for males 1

Genetic and Family Implications

Inheritance pattern: 6

• Autosomal dominant with variable penetrance 6
• 70% have positive family history, but 30% represent de novo mutations 6
• Critical pitfall: Absence of family history does NOT exclude PJS 6

Genetic testing recommendations: 1

• STK11/LKB1 mutation testing should be performed 1
• Detection rate is 66-94% even with modern techniques 1
• Negative genetic testing does NOT exclude clinical diagnosis of PJS 1

Epidemiology

Incidence: 1 in 50,000 to 1 in 200,000 live births 1, 6 Demographics: Affects all racial groups and both sexes equally 6 Average age at diagnosis: 23 years in males, 26 years in females 6