Peutz-Jeghers Syndrome: Symptoms, Cancer Risks, Screening, and Treatment Explained
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Peutz-Jeghers syndrome (PJS) is a rare genetic condition that causes polyps in the digestive tract and dark, freckle-like spots on the lips, mouth, hands, and feet. It is caused by a change in the STK11 gene and raises the lifetime risk of several cancers to roughly 40% to 93% [1]. There is no cure, but regular screening and polyp removal starting in childhood can find problems early and prevent complications such as intestinal blockage [1] [2].
Quick Answer
Peutz-Jeghers syndrome is a rare inherited condition that causes polyps in the digestive tract and dark spots on the lips, mouth and skin. People with it have a lifetime cancer risk of roughly 40% to 93%. Management means lifelong scheduled screening and removing polyps before they cause complications. Sudden severe belly pain or heavy rectal bleeding needs emergency care. [1] [2]
What the research says
A systematic review put the lifetime risk of any cancer at 37% to 93%. The review covered 21 articles, including 20 cohort studies with a total of 1,644 patients. Of these, 349 developed 384 malignancies at an average age of 42 years. Colorectal cancer was the most common, followed by breast, small bowel, gastric, and pancreatic cancers, and relative risks compared with the general population ranged from 9.9 to 18 (van Lier et al., Am J Gastroenterol, 2010).
Combined small-bowel imaging and enteroscopy reduced polyp burden, but guidelines rest mostly on expert opinion. A review reported that wireless capsule endoscopy, magnetic resonance enterography, and device-assisted enteroscopy used together are effective in reducing the polyp burden and so the risk of bleeding and intussusception. It notes that current screening and surveillance guidelines are mostly based on expert opinion rather than evidence (Tacheci et al., Curr Opin Gastroenterol, 2021).
Gaps remain in the evidence on surveillance, chemoprevention, and quality of life. A progress report found pathogenic germline variants in the STK11 gene in most patients, including cases of mosaicism and structural variants. It concluded that studies of the effect of surveillance and of chemoprevention are lacking, and that the effects of PJS on mental health, education, and family planning are insufficiently addressed (Jelsig et al., Fam Cancer, 2024).
Research summaries are based on article abstracts retrieved from PubMed.
What Is Peutz-Jeghers Syndrome?
Peutz-Jeghers syndrome (pronounced POOTZ-JAH-erz) is a rare genetic condition with two hallmark features that occur together [1]:
Feature | What Happens |
Hamartomatous polyps | Tissue growths in the digestive tract, usually in the small intestine, stomach, or colon. |
Dark spots | Freckle-like pigment spots on the lips, inside and around the mouth, on the genitals, and on the hands and feet. |
Hamartomatous polyps are made of regular tissue that grows in a disorganized way. Most polyps in PJS are not cancerous or precancerous, and the chance of any single polyp becoming cancer is probably low, although other types, including precancerous adenomatous polyps, can also form. The syndrome itself, however, is linked to a very high risk of several cancers, which is why lifelong screening matters [1]. The dark spots usually appear in childhood and may fade in adulthood [1].
What are the symptoms of Peutz-Jeghers syndrome?
Peutz-Jeghers syndrome is best known for freckle-like dark spots, often on the lips, while digestive polyps cause symptoms when they bleed, grow large or block the intestines.
Signs from polyps
Polyps in the digestive tract tend to cause symptoms when they bleed, grow large, or block part of the intestines [1]:
Symptom | Why It Happens |
Blood in the stool (red streaks or black stool) | Polyps bleeding in the digestive tract. |
Tiredness and weakness | Iron deficiency anemia from slow blood loss over time. |
Belly pain | Polyps growing or partly blocking the bowel. |
Vomiting | Intestinal blockage. |
Diarrhea | Irritation in the digestive tract. |
Dark skin spots
The most recognizable sign of PJS is the cluster of freckle-like spots. They often appear before age 5, may fade over time, and often remain inside the mouth [1]:
Lips: often the first place, usually before age 5.
Inside and around the mouth: spots here often remain in adulthood.
Genitals: can appear in childhood.
Fingers, palms, and soles of the feet: may fade with age.
Less common signs
A smaller number of people have symptoms involving the reproductive organs. Boys can develop estrogen-making tumors of the testicles that cause breast growth (gynecomastia), and girls can develop ovarian tumors that may lead to early puberty [1].
When to see a doctor
See a healthcare professional if new dark spots appear on the lips, around or inside the mouth, or on the genitals, hands, or feet, especially in a child, because these can be early signs of PJS. Seek care as soon as possible for any of the polyp symptoms above [1]. Get emergency care right away for [1]:
Emergency Sign | Possible Problem |
Sudden severe belly pain or repeated vomiting | Intussusception (the bowel slides into itself) or a blockage. |
Heavy rectal bleeding, or rectal bleeding with feeling very weak or dizzy | Serious blood loss. |
What causes Peutz-Jeghers syndrome?
PJS is caused by a mutation in the STK11 gene, which helps control how cells grow, repair themselves, and die. When the gene does not work as usual, cells may grow in an unorganized way, which can produce polyps [1].
Inheritance | What the Numbers Mean |
Inherited mutation | About 80% to 90% of people with PJS inherit the gene change from a parent. |
New (de novo) mutation | About 10% to 20% have a mutation that appears for the first time. Why this happens is not known. |
Chance per pregnancy | PJS is autosomal dominant, so each child of an affected parent has a 50% chance of inheriting it. |
The dark spots come from pigment (melanin) building up in the skin. Researchers do not know exactly why hamartomatous polyps form, but they think the STK11 change affects how cells grow and divide, allowing polyps to develop [1].
What are the risk factors for Peutz-Jeghers syndrome?
Family history is the main risk factor. If either parent has PJS, each child has a 50% chance of inheriting it. Both children and adults can have PJS. About a third of people with PJS have symptoms during their first 10 years of life, and by age 20 about 60% have symptoms [1]. Family members of someone with PJS usually should be screened and tested [1].
What complications can Peutz-Jeghers syndrome cause?
Cancer is the main long-term complication of Peutz-Jeghers syndrome, which also causes noncancerous tumors and polyp-related problems. The lifetime risk of cancer is roughly 40% to 93% and rises with age, and the average age at diagnosis is 42 [1]. Some common cancer types and the percentage of people with PJS who develop them over a lifetime are [1]:
Cancer Type | Lifetime Risk |
Breast | 32% to 54% |
Colon | 39% |
Pancreatic | 11% to 36% |
Stomach | 29% |
Ovarian | 21% |
Small bowel | 13% |
Cervical | 10% |
Uterine (endometrial) | 9% |
Testicular | 9% |
Lung | 7% to 17% |
PJS also causes noncancerous tumors in some people. Boys can develop Sertoli cell testicular tumors that make estrogen, causing gynecomastia and affecting height. Girls and women can develop sex cord ovarian tumors, which usually are not cancerous but can lead to early puberty [1].
Polyps can also cause gastrointestinal bleeding leading to iron deficiency anemia, intestinal blockage that may need surgery, and intussusception [1].
Can Peutz-Jeghers syndrome be prevented?
Peutz-Jeghers syndrome cannot be prevented, because it is an inherited genetic condition. Family members can have genetic testing, and if the gene change is found, regular screening can find polyps, cancer, and other problems early, before they become an emergency, when treatment is more likely to succeed [1].
How is Peutz-Jeghers syndrome diagnosed?
Peutz-Jeghers syndrome is diagnosed from symptoms, medical and family history and sometimes test results, including genetic testing for a change in the STK11 gene. You can be diagnosed with PJS if you have any of the following [2]:
Two or more hamartomatous polyps in the digestive tract.
Dark spots on the skin around or inside the mouth, or on the genitals, hands, or feet, combined with a family history of PJS.
Any number of hamartomatous polyps combined with a family history of PJS or with characteristic dark spots.
A genetic test that shows a pathogenic or likely pathogenic change in the STK11 gene.
Tests used in diagnosis and screening
Test | What It Reaches | What It Can Do |
Colonoscopy | The entire colon | Examine the colon, and remove or sample polyps. |
Upper endoscopy | Esophagus, stomach, and the first part of the small intestine | Examine and remove polyps. |
Capsule endoscopy | Parts of the small intestine a scope cannot reach | A vitamin-sized camera is swallowed and usually leaves in a bowel movement within a few days. |
Balloon-assisted enteroscopy | Deep small intestine | Examine polyps closely and sometimes remove them. |
Lab tests | Tissue samples | A pathologist examines polyp tissue to find out what type of polyp it is. |
If a capsule endoscopy cannot be done, MRI or MR enterography (no radiation) or a CT scan or CT enterography (a small radiation dose) can be used to view the small intestine [2].
Genetic testing
Genetic testing uses a blood sample. Finding a disease-causing STK11 change can confirm PJS, but not finding one does not rule it out, because some people with PJS do not have the gene change. In those people the diagnosis rests on the polyp features, the typical freckling pattern, and family history. If a gene change is found, testing may be recommended for family members [2].
Ongoing screening schedule
Which tests and how often depends on age, sex, and personal history [2]:
Screening | Typical Starting Point |
Colonoscopy and upper endoscopy | Often ages 8 to 10, or earlier with symptoms. If no polyps are found, testing may restart at age 18. If polyps are found, or after age 18, every 2 to 3 years, sometimes more often. |
Small intestine imaging (capsule endoscopy or MR or CT enterography) | Often starting between ages 8 and 10, then every 2 to 3 years if polyps are found or after age 18. |
Yearly physical exam for girls | Starting at age 8 or at diagnosis, to check for early puberty, plus a blood test for anemia. |
Yearly physical exam for boys | Usually starting at ages 8 to 10, to check the testicles for tumors and for breast growth, plus a blood test for anemia. |
Women: pelvic exam, Pap smear, and transvaginal ultrasound | Yearly, often starting around ages 18 to 20. |
Women: breast exam, mammogram, and breast MRI | Often starting around age 30. Breast exams every 6 to 12 months, mammography and breast MRI yearly. |
Pancreatic screening (MRI, MR cholangiopancreatography, or endoscopic ultrasound) | Usually starting around age 30, yearly. |
Conditions that resemble PJS
Condition | Key Differences from PJS |
Juvenile polyposis syndrome | Multiple hamartomatous polyps and a higher cancer risk, but no dark spots. Linked to the BMPR1A or SMAD4 genes. |
Familial adenomatous polyposis (FAP) | Many adenomatous polyps, most often in the large intestine, and no dark spots. Linked to the APC gene. |
Hereditary hemorrhagic telangiectasia (HHT) | No polyps, but lacy red vessels or tiny red spots on the lips, face, fingertips, and tongue, and often nosebleeds. It can occur together with PJS in about 20% of people with PJS. |
How is Peutz-Jeghers syndrome treated?
Peutz-Jeghers syndrome has no cure, but its polyps, cancer risk and other complications can be managed. Treatment focuses on screening for and managing polyps, cancer, and other complications over time [2].
Polypectomy: polyps can be removed during upper endoscopy, colonoscopy, and balloon-assisted enteroscopy. Very small polyps may be removed with forceps, small to medium polyps with a wire loop called a snare, and sometimes an electric current cuts a polyp and prevents bleeding. Removing polyps helps prevent bleeding, blockage, and intussusception.
Surgery: used for polyps too large to be removed safely, for intussusception, for polyps that block the intestine or cause bleeding that cannot be controlled, and if cancer is found.
Managing anemia: blood tests check for iron deficiency anemia. Treatment is to find and stop the source of bleeding, such as by removing bleeding polyps. People who lose a lot of blood may need IV fluids, possibly blood transfusions, and prescribed iron.
Cancer treatment: cancers caused by PJS are treated the same as cancer in someone without PJS.
Life expectancy with PJS varies. Because the lifetime cancer risk is between roughly 40% and 93% and rises with age, the goal of treatment is to find and treat cancer early, when it may be more successful, while reducing symptoms and preventing other complications [2].
Complementary approaches, coping, and support
Research on drug-based prevention (chemoprevention) in PJS is lacking [5], so scheduled screening and polyp removal remain the core of care. Talk with your healthcare professional before using any supplement so it does not interfere with screening or treatment. Living with PJS means living with a schedule of tests, so support groups for inherited cancer syndromes and genetic counseling can help families understand risk, plan screening, and decide about testing for relatives. The impact on mental health and family planning is an area that needs more research [5].
How should you prepare for a Peutz-Jeghers syndrome appointment?
Preparing questions ahead of a Peutz-Jeghers syndrome appointment helps, because time with a healthcare professional may be limited. For PJS, useful questions include [2]:
Category | Questions to Ask |
Heredity | What are the chances I will pass this to my children? Should my family members be tested for PJS? |
Cancer risk | What is my risk of cancer, and how can I lower it? |
Screening | How often do I need screening tests, and what kind? |
Polyps | How many polyps have been found, and what kind are they? |
Surgery | Will I need surgery? When, and what kind? |
Follow-up | What kind of follow-up and treatment do I need? |
Genetics | How accurate is genetic testing? |
Conclusion
Peutz-Jeghers syndrome is rare, but it is manageable when it is caught early and monitored consistently. The combination of childhood skin spots and hamartomatous polyps raises the lifetime risk of several cancers, yet a structured screening plan finds problems while they are still treatable [1] [2]. If you or a child has dark spots on the lips or mouth, a family history of polyps or early cancer, or unexplained digestive bleeding, ask a healthcare professional whether PJS screening is appropriate. A gastroenterologist or genetic counselor can help build a screening plan for your family.
Frequently Asked Questions
What is Peutz-Jeghers syndrome?
Peutz-Jeghers syndrome (PJS) is a rare genetic condition caused by a change in the STK11 gene. It causes polyps in the digestive tract and freckle-like dark spots on the lips, mouth, hands, feet, and genitals, and it raises the risk of several cancers [1].
Is Peutz-Jeghers syndrome a form of cancer?
No. The most common polyps in PJS, hamartomatous polyps, are made of ordinary tissue growing in a disorganized way, and any single polyp probably has a low chance of becoming cancer. The syndrome itself, however, raises the lifetime risk of cancer to roughly 40% to 93% [1].
Which cancers are people with PJS most likely to develop?
Lifetime risks include colon (39%), breast (32% to 54%), stomach (29%), pancreatic (11% to 36%), ovarian (21%), small bowel (13%), cervical (10%), uterine (9%), testicular (9%), and lung (7% to 17%) [1].
How is Peutz-Jeghers syndrome inherited?
PJS is autosomal dominant, so one changed copy of STK11 is enough. About 80% to 90% of people inherit it from a parent, giving each child of an affected parent a 50% chance of inheriting it. The other 10% to 20% have a new (de novo) mutation [1].
What do the dark spots of PJS look like, and where do they appear?
The dark spots of PJS look like freckles and often appear before age 5 on the lips, in and around the mouth, and on the genitals, fingers, palms, and soles. They may fade over time but often remain inside the mouth [1].
Are hamartomatous polyps precancerous?
Most PJS polyps are not cancerous or precancerous, but adenomatous (precancerous) polyps can also form in PJS. Polyps are removed mainly to prevent bleeding, blockage, and intussusception [1] [2].
When should screening for PJS begin?
Colonoscopy and upper endoscopy often begin between ages 8 and 10, or earlier if there are symptoms, with small intestine imaging on the same schedule. Breast, pelvic, and pancreatic screening starts around ages 18 to 20 and around age 30, depending on sex and history [2].
What is intussusception and why is it an emergency?
Intussusception is when one part of the bowel slides into another like a telescope, causing a blockage. It can cause sudden severe belly pain or repeated vomiting and is dangerous if not treated quickly [1].
How is Peutz-Jeghers syndrome diagnosed?
Diagnosis can be made with two or more hamartomatous polyps, dark spots plus a family history, any number of polyps plus a family history or characteristic spots, or a disease-causing STK11 change on genetic testing. A negative test does not rule out PJS [2].
Can Peutz-Jeghers syndrome be cured or prevented?
There is no cure and no known way to prevent PJS itself. Care focuses on screening, polyp removal, surgery when needed, and standard cancer treatment if cancer develops [1] [2].
Should family members of someone with PJS get tested?
Yes. Family members usually should be screened and tested. If a gene change is found, genetic testing may be recommended for relatives so screening can start early [1] [2].
Related Resources
Related on Rinnit:
External resources for deeper reading:
American Cancer Society. Peutz-Jeghers Syndrome (PJS). American Cancer Society. Accessed October 30, 2026. https://www.cancer.org/cancer/risk-prevention/genetics/family-cancer-syndromes/peutz-jeghers-syndrome.html — overview of the syndrome and its cancer risks
Amos CI, Wagner A. Peutz-Jeghers Syndrome. In: Adam MP, Bick S, Mirzaa GM, et al., eds. GeneReviews®. University of Washington, Seattle; 1993-2026. Updated October 6, 2026. PMID 20301443. https://www.ncbi.nlm.nih.gov/books/NBK1266/ — clinical genetics reference
National Comprehensive Cancer Network. Genetic/Familial High-Risk Assessment: Colorectal, Endometrial, and Gastric. NCCN Guidelines. Accessed October 30, 2026. https://www.nccn.org/guidelines/guidelines-detail?category=2&id=1544 — colorectal, endometrial, and gastric guidelines
References
Mayo Clinic Staff. Peutz-Jeghers syndrome: Symptoms and causes. Mayo Clinic. February 21, 2026. https://www.mayoclinic.org/diseases-conditions/peutz-jeghers-syndrome/symptoms-causes/syc-20595244
Mayo Clinic Staff. Peutz-Jeghers syndrome: Diagnosis and treatment. Mayo Clinic. February 21, 2026. https://www.mayoclinic.org/diseases-conditions/peutz-jeghers-syndrome/diagnosis-treatment/drc-20595294
van Lier MGF, Wagner A, Mathus-Vliegen EMH, et al. High cancer risk in Peutz-Jeghers syndrome: a systematic review and surveillance recommendations. Am J Gastroenterol. 2010;105(6):1258-1264. PMID: 20051941. DOI: 10.1038/ajg.2009.725
Tacheci I, Kopacova M, Bures J. Peutz-Jeghers syndrome. Curr Opin Gastroenterol. 2021;37(3):245-254. PMID: 33591027. DOI: 10.1097/MOG.0000000000000718
Jelsig AM, Karstensen JG, Overeem Hansen TV. Progress report: Peutz-Jeghers syndrome. Fam Cancer. 2024;23(4):409-417. PMID: 38493229. DOI: 10.1007/s10689-024-00362-7
Medical disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have about a medical condition.
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