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PJS & JPS

Peutz-Jeghers Syndrome (PJS)

Overview:

  • Inheritance Pattern: Autosomal-dominant hereditary cancer syndrome.
  • Lifetime Risk of CRC: 39%.
  • Primary Characteristics:
    • Hamartomatous polyps (mainly gastrointestinal).
    • Mucocutaneous pigmentation (dark blue or brown macules on the lips, buccal mucosa, hands, and feet).
    • High predisposition to both intestinal and extraintestinal cancers (90% lifetime risk).

Genetics:

  • Caused by a mutation in the STK11/LKB1 gene on chromosome 19p.
  • About 50% inherited from a parent; the rest are due to spontaneous mutations.

Polyp Characteristics:

  • Location: Most common in the small bowel, followed by the colon, stomach, and rectum.
  • Histology:
    • Polyps arise from muscularis mucosa.
    • Contain smooth muscle bundles within the lamina propria, differentiating them from juvenile polyps, which arise from the lamina propria.

Diagnosis Criteria (World Health Organization):

  1. Three or more histologically confirmed Peutz-Jeghers polyps.
  2. Any number of PJ polyps with a family history of PJS.
  3. Characteristic mucocutaneous pigmentation with a family history of PJS.
  4. Any number of Peutz-Jeghers polyps and mucocutaneous pigmentation.

Cancer Risk:

  • Colorectal cancer (most common)
  • Gastric, pancreatic, lung, breast, uterine, cervical, testicular, and ovarian cancers.

Surveillance Recommendations:

  • Age 8 to 10: Initial small bowel evaluation.
  • Age 18: Repeat small bowel evaluation.
  • Colon and upper GI screening: Start in the late teens, repeat every 2-3 years.
  • Males: Annual testicular examination from age 10.
  • Females: Annual pelvic exam and Pap smear from age 18-20, breast physical exams every 6 months, yearly mammogram and breast MRI starting at age 25.
  • Pancreatic cancer screening: Endoscopic ultrasound or MRCP starting at age 25-30.

Management:

  • Polypectomy: Key for managing polyps >1 cm in size to prevent bleeding and intussusception.
  • Surgery: Reserved for symptomatic cases like obstruction or bleeding; goal is to preserve as much bowel as possible.

Juvenile Polyposis Syndrome (JPS)

Overview:

  • Inheritance Pattern: Autosomal-dominant.
  • Lifetime Risk of CRC: 10% to 38%.
  • Primary Characteristics:
    • Hamartomatous polyps throughout the gastrointestinal tract.
    • Common symptoms include GI bleeding, iron-deficiency anemia, rectal prolapse, abdominal pain, and diarrhea.

Genetics:

  • Linked to mutations in SMAD4 (chromosome 18q) and BMPR1A (chromosome 10q).
  • Pathogenic mutations in these genes are detected in 40%-50% of patients.

Polyp Characteristics:

  • Location: Most common in the colorectum but can occur throughout the GI tract (e.g., stomach, duodenum).
  • Histology:
    • Juvenile polyps are characterized by dilated cystic glands and expanded lamina propria with inflammatory infiltrates (neutrophils, eosinophils, lymphocytes).

Diagnosis Criteria:

  1. Five or more juvenile polyps in the colorectum.
  2. Multiple juvenile polyps throughout the GI tract.
  3. Any number of juvenile polyps with a family history of juvenile polyposis.

Cancer Risk:

  • Colorectal cancer is the most common malignancy.
  • There is also a risk for cancers in the stomach, pancreas, and small intestine.

Surveillance Recommendations:

  • Colonoscopic screening: Start between ages 12 to 15.
    • If no polyps are found, repeat every 2 to 3 years.
    • If polyps are present and removed, perform annually.

Management:

  • Polypectomy: For endoscopically manageable polyps.
  • Surgical Indications:
    • High-grade dysplasia or cancer.
    • Polyp burden that cannot be controlled endoscopically.
    • Prophylactic colectomy may be considered in patients with poor surveillance compliance or a family history of CRC.

Surgical Options:

  1. Subtotal colectomy and ileorectal anastomosis (IRA).
  2. Segmental colectomy or total colectomy with ileal pouch-anal anastomosis (IPAA).
  3. In case of colonic and rectal polyps, proctocolectomy may be necessary.

Comparison of Polyp Histology in Peutz-Jeghers Syndrome (PJS) and Juvenile Polyposis Syndrome (JPS)

Syndrome Polyp Histology Key Features
Peutz-Jeghers Syndrome (PJS) - Hamartomatous polyps with smooth muscle bundles in the lamina propria of the stalk and head.
- Arise from muscularis mucosa, not lamina propria (unlike juvenile polyps). - High risk of CRC (39%) and various other cancers (90% lifetime cancer risk).
- Mucocutaneous pigmentation is a key clinical feature.
Juvenile Polyposis Syndrome (JPS) - Juvenile polyps characterized by dilated cystic glands and expanded lamina propria with an inflammatory infiltrate (neutrophils, eosinophils, lymphocytes). - Increased risk of colon cancer (10-38%).
- Polyps primarily in the colorectum but can occur throughout the GI tract.

Key Differences in Histology:

  • PJS Polyps: Arise from the muscularis mucosa with smooth muscle bundles, primarily in the small bowel but also found in the colon, stomach, and rectum. Unlike juvenile polyps, they lack cystic spaces and dilated glands.
  • JPS Polyps: Characterized by dilated cystic glands in an expanded lamina propria with an inflammatory infiltrate, more typical in the colorectum, though can be found throughout the GI tract.