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PTEN Hamartoma Tumor Syndrome

Also called: PHTS, Cowden syndrome, Cowden disease, Bannayan-Riley-Ruvalcaba syndrome, Proteus syndrome, Proteus-like syndrome, PTEN-related Proteus syndrome

PTEN hamartoma tumor syndrome is a genetic condition in which non-cancerous growths, called hamartomas, develop in different areas of the body. It can be passed down from parent to child (inherited). People with PTEN hamartoma tumor syndrome are at higher risk of developing cancers of the:

  • Breast
  • Thyroid
  • Kidney
  • Uterus
  • Colon
  • Rectum
  • Skin

Along with hamartomas, patients can have other physical signs, including larger-than-average head size, abnormal skin growths, and problems with mental function and learning.

Cancer risk with PTEN hamartoma tumor syndrome

People with PTEN hamartoma tumor syndrome are at high risk for certain cancers. These cancers generally occur in adults who have the condition, not in children. The average age of cancer diagnosis is about 30–50 years old.

Thyroid cancer is the exception. It sometimes occurs in children with PTEN hamartoma tumor syndrome.

Type of Cancer Lifetime Risk
Breast 85% (in women)
Thyroid 35%
Renal cell (kidney) 35%
Endometrium (lining of uterus) 28%
Colorectal 9%
Melanoma (skin cancer) More than 5%

People with PTEN hamartoma tumor syndrome rarely develop a type of brain tumor called cerebellar dysplastic gangliocytoma (also called adult-onset Lhermitte-Duclos disease). The exact risk of developing this type of tumor is unknown because it is so rare.

Signs of PTEN hamartoma tumor syndrome

People with PTEN hamartoma tumor syndrome may have other physical signs besides the hamartomas. Not all people with this syndrome will have all of these.

Physical Signs Estimated Risk
Larger-than-average head (macrocephaly) 94%
Skin growths or coloring:
- Smooth, white skin growths on the face (trichilemmomas)
- Smooth, flesh-colored skin growths on the hands or feet (acral or plantar keratosis)
- Smooth skin growths in the mouth (oral papillomas)
- Freckling of the penis skin in boys and men
More than 90%
Non-cancerous growths (polyps) in the digestive system 90%
Non-cancerous growths (nodules, goiter, adenoma) in the thyroid gland 75%
Non-cancerous growths (fibrocystic disease) in the breast 67%
Intellectual disability, learning disability, or autism spectrum disorder (learning problems) 47-89%

Other physical signs may include:

  • Non-cancerous growths in the uterus (fibroids)
  • Non-cancerous growths of fatty cells under the skin (lipomas)
  • Muscle weakness  
  • An abnormally curved spine (scoliosis)

Causes of PTEN hamartoma tumor syndrome

PTEN hamartoma tumor syndrome is caused by changes in a gene known as PTEN. Genes carry information telling cells within the body how to function. The PTEN gene helps control how and when cells grow, divide, and die.

How PTEN hamartoma tumor syndrome is inherited

Most people carry 2 working copies of the PTEN gene in their cells. One copy is inherited from the mother and 1 from the father. Cells from people with PTEN hamartoma tumor syndrome carry 1 working copy of PTEN and 1 copy that is changed. This change causes the gene to not work properly. It is called a PTEN mutation.

Inherited or new mutation

Between 10–50% of children with PTEN hamartoma tumor syndrome inherit the PTEN gene mutation from a parent who also has the syndrome. The rest have a new PTEN mutation that did not come from a parent.

Children with a new PTEN mutation have no history of the syndrome in their family. In these cases, the change either happened in an egg or sperm cell when the child was formed or in 1 of the child’s cells during pregnancy. These children are the first in their families to have PTEN hamartoma tumor syndrome.

No matter how it comes about, everyone with PTEN hamartoma tumor syndrome has a 50% (1 in 2) chance of passing it on to their children.

When cancer occurs

If the working copy (normal copy) of the PTEN gene undergoes changes within a cell, then that cell can begin to grow in an abnormal way. When both copies of the gene are changed, cancer can develop. That is why people with PTEN hamartoma tumor syndrome have a higher risk of cancer.

Diagnosis of PTEN hamartoma tumor syndrome

Health history

A health care provider may suspect that your child has PTEN hamartoma tumor syndrome after studying their medical and family cancer history. 

This information helps the health care provider and the genetic counselor know if:

  • There are more cancers than normal in your family
  • These cancers happened at a younger age than expected
  • The cancers are those that are seen in PTEN hamartoma tumor syndrome

Your provider or genetics counselor may recommend PTEN genetic testing if they suspect PTEN hamartoma tumor syndrome.

Learn more about types of genetic tests.

Genetic testing for PTEN hamartoma tumor syndrome

A blood sample is sent to a genetic testing lab. The lab runs genetic tests that look for changes in the PTEN gene. 

If your child has a PTEN mutation, a genetic counselor will:

  • Find out if other family members should consider testing for a PTEN mutation 
  • Help your family understand the increased cancer risk from PTEN hamartoma tumor syndrome
  • Give you information to help with your decisions about prenatal genetic testing

Genetic testing before or during pregnancy

Parents may choose to do prenatal testing to find out if a pregnancy is affected with a known PTEN mutation. Testing may take place either before pregnancy occurs or during pregnancy.

You should work with a genetic counselor to review the pros and cons of the test. The genetic counselor can also help you prepare for the test results.

Testing before pregnancy is called preimplantation genetic testing (PGT). This special type of genetic testing is done along with in vitro fertilization (IVF). PGT tests embryos for a known PTEN mutation before a provider places the embryo into the uterus.

Testing during pregnancy can help providers see if a pregnancy has a known PTEN mutation. A doctor gathers cells from the pregnancy in 1 of 2 ways:

  • Chorionic villus sampling (CVS) is done during the first 3 months of pregnancy (1st trimester).
  • Amniocentesis is done after the first 3 months of pregnancy (2nd trimester or later).

After tissue collection, the lab checks the sample for the known PTEN mutation. Both tests carry minor risks. Discuss risks with an experienced health care provider or a genetic counselor.

Special concerns for genetic testing

Take time to think carefully about the benefits and risks of genetic testing. Speak with a genetic counselor before testing. If you decide to get tested, talk with your health care provider or a genetic counselor about your results so you can understand what they mean. 

Sometimes, children or adults with PTEN hamartoma tumor syndrome feel sad, anxious, or angry after getting their test results. Parents may feel guilty if they pass the PTEN gene mutation to 1 or more of their children. People with a PTEN gene mutation may also have trouble getting disability or life insurance. 

Read more about genetic discrimination.

Monitoring and follow-up care for PTEN hamartoma tumor syndrome

People with the syndrome should be monitored and have follow-up with a health care provider who knows the condition well.

Recommended screenings for children with PTEN hamartoma tumor syndrome:

  • Yearly physical exams by a health care provider who knows this syndrome well.
  • Thyroid ultrasound starting at diagnosis and repeated every year.
  • Regular assessments of development and learning progress as recommended by your health care provider.

Recommended screenings for adults with PTEN hamartoma tumor syndrome:

  • Yearly physical exams by a health care provider who knows this syndrome well.
  • Thyroid ultrasound every year.
  • Skin exam by a dermatologist (skin doctor) may be needed for some patients.
  • For women: Clinical breast exam by a health care provider starting at age 25 or 5–10 years before the earliest known breast cancer in the family, whichever is earlier. Repeated every 6–12 months.
  • For women: Breast imaging every 6 months alternating mammogram with breast MRI starting at age 30–35 or 5–10 years before the earliest known breast cancer in the family, whichever is earlier. Consider risk-reducing mastectomy.
  • For women: Yearly random endometrial biopsy and/or ultrasound of the endometrium (uterus) starting at age 30–35. A biopsy is done by suctioning a small amount of tissue out through the vagina and sending it to the lab to be tested for cancer cells. Consider risk-reducing hysterectomy after completing childbearing.
  • Kidney imaging by ultrasound, computed tomography (CT) or magnetic resonance imaging (MRI) starting at age 40 and repeated every 2 years. Note: Ultrasound or MRI is preferred.
  • Colonoscopy starting at age 35 (unless symptoms arise earlier or the patient has a close relative with colon cancer younger than age 40). Colonoscopy should be done every 5 years or more often if patient has symptoms or if polyps are found.

If a family member with PTEN hamartoma tumor syndrome was diagnosed with a certain type of cancer, then screening for other family members will likely happen sooner than described above. Health care providers usually start screening for that type of cancer at least 5 years before the earliest known diagnosis in the family. For example, if a family member with PTEN hamartoma tumor syndrome developed breast cancer at age 35, it is recommended that other family members with the syndrome start breast cancer screening at age 25–30.

It is possible that these recommendations may change over time as health care providers learn more about PTEN hamartoma tumor syndrome. Parents should discuss all screening options for their child with a health care provider who knows this syndrome well.

Living with PTEN hamartoma tumor syndrome

People of any age with PTEN hamartoma tumor syndrome have a higher risk of cancer. They should monitor their health and adopt healthy habits throughout life. It is important to continue to have regular physical checkups and screenings. The goal is to find any cancer early at the most treatable stage.

Problems to watch for

People should watch closely for signs or symptoms that could signal cancer:

  • Unexplained weight loss
  • Loss of appetite
  • Pain in abdomen (belly)
  • Blood in the stool or changes in bowel habits
  • Aches, pains, lumps, or swelling that cannot be explained
  • Headaches or changes in vision or nerve function that do not go away

Seek medical help if anything unusual appears.

Maintain a healthy lifestyle

Habits that will help you maintain a healthy lifestyle include:

  • Eat a healthy diet with lots of fruits and vegetables
  • Get regular exercise
  • Avoid smoking or using tobacco products
  • Avoid secondhand smoke
  • Avoid excess sun exposure and always wear sunscreen, a hat, and protective clothing when out in the sun

PTEN hamartoma tumor syndrome care at             St. Jude

The St. Jude Cancer Predisposition Program is dedicated to diagnosing and screening children with a genetic predisposition for cancer. Our program offers the best clinical care possible. We engage in cutting-edge research to gain more information about genetic disorders and cancer, and to improve the care and treatment for patients who are affected by these conditions. Learn more about the Division of Cancer Predisposition at St. Jude.

Our genetic counselors, clinicians, genetics nurse practitioners, and research assistants work together to provide patients with:

  • A complete health history
  • A record of cancer that happened over the past 3 generations (family tree or pedigree) to see how diseases were passed down
  • Physical exams to check for genetic disease
  • Confidential genetic counseling and testing
  • Cancer screenings for those with genetic disease to detect and treat cancer as soon as it occurs
  • Recommended cancer treatments and ways to reduce cancer risk
  • Genetic testing for immediate (1st degree) relatives

PTEN hamartoma tumor syndrome increases your child’s risk for cancer. 

Related clinical trials

St. Jude offers clinical trials and cancer research studies for children, teens, and young adults who have cancers associated with PTEN hamartoma tumor syndrome.

Learn more about clinical research at St. Jude.

GENETX: Assessing Gene Therapy Communication Needs

Study goal:

To learn more about participants beliefs, attitudes, and questions about gene therapy to help make web-based resources to share information. This could help patients make treatment decisions.


18 to 35 years old with rare genetic diseases

Published results
G4K: Genomes for Kids

Study goal:

The main goal of this study is to learn more about the reasons childhood tumors form and how to treat them better.

TBANK: Collecting, Banking, and Distributing Human Tissue Samples in St. Jude Biorepository

Study goal:

To provide a high-quality repository of tumor and normal samples to facilitate translational research performed by St Jude faculty and their collaborators

PG4KDS: Clinical Implementation of Pharmacogenetics

Study goal:

1) Test each patient for hundreds of gene variations that might be important for drug use. All of the gene test results will be in the research laboratory, but as time goes on, the study will evaluate scientific evidence and selectively move test results for a few genes into the medical record if the evidence strongly shows that the result can help in better prescribing of drugs for patients; 2) Estimate how often pharmacogenetic test results are moved from research tests into a patient’s medical record; 3) Use methods to choose which of these tests should be put in the medical record; 4) Use computer-based tools in the electronic medical record to help doctors use gene test results when prescribing drugs; 5) Share feelings and concerns of patients and their families about gene test information being put in their medical record.

SJFAMILY: Study of Cancer in Families

Study goal:

The main purpose of this trial is to learn about the genetic causes of cancer. 


Younger than 50 years old

A statue of children running and holding hands

Seeking treatment at St. Jude

Patients accepted to St. Jude must have a disease we treat and must be referred by a physician or other qualified medical professional. We accept most patients based on their ability to enroll in an open clinical trial.

How to seek treatment

Contact the Physician / Patient Referral Office

Call: 1-888-226-4343 (toll-free) or 901-595-4055 (local)  | Fax: 901-595-4011 | Email: | 24-hour pager: 1-800-349-4334


Learn more

If you have questions about the Genetic Predisposition Clinic and care for PTEN hamartoma tumor syndrome, email our team at

Resources outside St. Jude