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Condition created 2026-08-19 · updated 2026-08-24
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Hamartomatous Polyposis Syndromes

Covers Peutz-Jeghers syndrome, juvenile polyposis syndrome, and Cowden syndrome — the three hamartomatous hereditary CRC syndromes. See Hereditary Colorectal Cancer Syndromes for how these fit among the other syndromes. PJS/JPS content is from a textbook reference chapter (Sabiston Ch52 - Colorectal Neoplasia & Colon Cancer Surgery); Cowden syndrome and the PJS chemoprevention note were added from a second textbook chapter (ASCRS Ch22 - Sporadic and Inherited Colorectal Cancer) — neither is primary literature.

Peutz-Jeghers syndrome (PJS)

Autosomal dominant hereditary cancer syndrome carrying a 39% lifetime CRC risk. Characterized by benign hamartomatous, primarily GI, polyps plus mucocutaneous pigmentation (dark blue or brown macules on the vermillion lip border, buccal mucosa, hands, feet). High predisposition to many intestinal and extraintestinal cancers — nearly 90% of PJS patients develop hamartomatous polyps, most commonly in the small bowel, followed by the colon, stomach, and rectum in decreasing frequency. Overall lifetime cancer risk is 90%, including colorectal (most common), gastric, pancreatic, lung, breast, uterine, cervical, testicular, and ovarian cancer.

Caused by mutation of the STK11/LKB1 gene (chromosome 19p). About half of PJS cases are inherited from a parent; the remainder occur with no family history (de novo).

Diagnosis (clinical, per WHO criteria — any one of):

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

Histologically, PJ polyps differ from adenomatous polyps in that they arise from an overgrowth of the muscularis mucosa rather than the lamina propria.

Surveillance (given the multi-organ cancer risk):

  • Small bowel evaluation begins ages 8–10; if normal, repeat at 18, then every 2–3 years.
  • Males: annual testicular physical exam starting age 10.
  • Females: annual pelvic exam plus Pap smear starting age 18–20; breast exams every 6 months plus yearly mammogram/breast MRI starting age 25.
  • Colonoscopy and upper endoscopy start in the late teens, repeated every 2–3 years, both genders.
  • Pancreatic cancer screening via endoscopic ultrasound or MRCP plus serum CA19-9 every 1–2 years starting age 25–30.

Management: polypectomy plays a key role. Asymptomatic gastric or colonic polyps >1 cm should be removed endoscopically. Small bowel polyps >1–1.5 cm, or those growing rapidly, should be removed to reduce future complications (bleeding, intussusception). Surgery is most commonly reserved for symptomatic disease — most often obstruction (from intussusception) or bleeding in the small bowel. Goal: remove the affected segment while preserving as much bowel as possible; may require push enteroscopy or combined laparoscopy/laparotomy with intraoperative endoscopy, since small bowel polyps aren't reliably visualized by other means. Similar to other polyposis syndromes, progression to malignancy is best treated with total colectomy with ileorectal anastomosis. STK11 chemoprevention: given STK11's role as a tumor suppressor and evidence for unchecked neoplastic growth in its absence, several trials with selective mTOR inhibitors (e.g. everolimus) have been attempted, but have been plagued by poor patient accrual given the rarity of PJS (per ASCRS Ch22 - Sporadic and Inherited Colorectal Cancer).

Juvenile polyposis syndrome (JPS)

Autosomal dominant inheritance, characterized by hamartomatous intestinal polyps. Lifetime colon cancer risk 10–38%; average age at diagnosis 34 years. Clinically diagnosed when there are 5 or more juvenile polyps in the colorectum, any number of juvenile polyps throughout the GI tract with a family history, or juvenile polyposis itself. Symptoms relate to the polyps: acute or chronic GI bleeding, iron-deficiency anemia, prolapsed rectal polyps, abdominal pain, diarrhea.

Two genes linked to JPS: SMAD4 (chromosome 18q) and BMPR1A (chromosome 10q). A pathogenic mutation in one of these two genes is detected in only 40–50% of JPS patients (i.e. genetic testing is far from fully sensitive). There is an increased cancer risk in affected individuals, with a malignant potential of at least 10% in patients with multiple juvenile polyps.

Screening: colonoscopy begins ages 12–15. Interval depends on findings — if no polyps, repeat in 2–3 years; when polyps are present and removed, colonoscopy should be repeated yearly.

Surgical indications: presence of high-grade dysplasia or cancer, or if the polyp burden cannot be effectively managed endoscopically. Prophylactic colectomy may be considered for patients with poor surveillance compliance or a family history of CRC. Surgical options for colorectal disease: subtotal colectomy with IRA, segmental colectomy, or total colectomy with IPAA.

Cowden syndrome (CS)

Also termed PTEN hamartoma tumor syndrome (PHTS), Cowden syndrome is caused by mutation of PTEN, a tumor suppressor gene regulating intracellular signaling and apoptosis. Bannayan- Riley-Ruvalcaba syndrome is a variant also typically caused by PTEN mutation. Colonic polyps are found in 95% of CS patients, ranging from few to hundreds in number and distributed throughout the colon. While hamartomatous polyps are the most common, multiple synchronous polyp types are often seen at colonoscopy, including adenomas, inflammatory polyps, ganglioneuromas, lipomas, and leiomyomas — a genuinely mixed polyp phenotype, unlike the single-histology picture in PJS/JPS.

CS patients have a lifetime risk of CRC of 9–16%, with cancer often developing before age 50. Those identified with this disorder should start surveillance colonoscopy at age 15, followed by repeat exams every 2 years thereafter. (Content per ASCRS Ch22 - Sporadic and Inherited Colorectal Cancer.)

  • Familial Adenomatous Polyposis (FAP) — the polyposis-syndrome counterpart with a different (adenomatous rather than hamartomatous) polyp phenotype; see that page for FAP/AFAP/MAP.
  • Hereditary Colorectal Cancer Syndromes — how these three syndromes fit among the other hereditary CRC syndromes, now updated to include Cowden syndrome, POLE/POLD1-related hereditary cancer, and serrated polyposis syndrome.
  • Colorectal Polyps — general hamartoma content; see that page's Serrated polyposis syndrome subsection for the polyp-morphology counterpart among non-adenomatous polyposis syndromes.

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