What Is Cowden Syndrome?

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Cowden syndrome is a rare genetic disorder that most noticeably causes hamartomas (benign, or noncancerous, tumors) on various parts of the body and an increased risk for certain types of cancer, especially breast, uterine, and thyroid cancers.

People with Cowden syndrome also typically have a larger-than-average head size and may experience developmental or learning delays. Experts estimate that Cowden syndrome affects roughly one in 200,000 people.

Understanding Cowden Syndrome

Verywell / Theresa Chiechi

First described in 1963, Cowden syndrome (also called Cowden's disease) is named after the family with the initial reported symptoms. Researchers later discovered the gene responsible for a majority of Cowden syndrome cases: the PTEN gene, which helps suppress the growth of tumors in the body.

Cowden syndrome is part of a group of disorders that all have a PTEN gene mutation in common, and it's sometimes referred to as PTEN hamartoma syndrome or multiple hamartoma syndrome.

Cowden Syndrome Symptoms

Cowden syndrome has several main symptoms. The most common are:

  • Multiple tumor-like growths called hamartomas on various parts of the body
  • Increased risk for developing certain cancers

In Cowden syndrome patients, hamartomas are commonly found on the skin and in the lining of the nose and mouth (or mucous membranes). They usually develop by the time a person reaches adulthood.

Depending on the location, hamartomas either cause pain or discomfort from pressure on the surrounding organs and tissues or no pain at all.

Compared to the general population, people with Cowden syndrome have an increased risk of developing cancer, particularly breast, colorectal, kidney, uterine, and thyroid cancers.

Cowden syndrome patients usually develop these cancers at younger ages than most people—sometimes as early as their 30s—and are more likely to develop more than one cancer throughout their lifetime.

Additional signs and symptoms of Cowden syndrome include:

  • Macrocephaly (a larger-than-average head size)
  • Trichilemmomas (benign hair follicle tumors)
  • Papillomatous papules (white, raised, smooth skin bumps located in the mouth) 
  • Delayed development, intellectual disability, or an autism spectrum disorder diagnosis


Cowden syndrome is what’s known as an autosomal dominant genetic mutation. This means it's a genetic abnormality inherited through your parents.

For example, if a parent has Cowden syndrome (with one mutated gene and one normal gene), there is a 50-50 chance that the child will inherit the mutated gene, and Cowden syndrome will develop.

PTEN Gene Mutation

Cowden syndrome is most commonly associated with a mutation (change) in the PTEN gene. The PTEN gene is one of the body’s tumor suppressor genes. Tumor suppressor genes make proteins that regulate the growth of cells. They play an important role in preventing the development of cancer cells.

When it functions normally, PTEN can help control cell growth. But when this gene is mutated, it can’t perform its job properly and cells can grow out of control. The result is the development of various noncancerous and cancerous tumors that are characteristic of Cowden syndrome.

Other Names

Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome, and PTEN-related Proteus syndrome, and a few other conditions have all been identified as having a PTEN gene mutation. This related group of disorders is known in the medical field as PTEN hamartoma tumor syndrome, or PHTS.

Other Gene Mutations

Far less commonly, Cowden syndrome can be caused by mutations in other genes, such as KLLN, SDHB, SDHC, SDHD, PIK3CA, or AKT1 genes, which have various functions. Interestingly, some people with suspected Cowden syndrome do not show a mutation in any of these genes. In those cases, the exact cause of Cowden syndrome is unknown.


Cowden syndrome can be difficult to diagnose, which is why there may be a variety of doctors involved in your care if it is suspected. Aside from your primary care doctor, this medical team may include an oncologist (a doctor specializing in cancer) and a geneticist or genetics counselor. These healthcare professionals will work together to give an accurate diagnosis.

To form a Cowden syndrome diagnosis, experts will look for at least a few of the following signs for confirmation, depending on your individual circumstance:

  • Multiple hamartomas
  • Macrocephaly
  • Breast, thyroid, or endometrial cancer
  • A biopsied trichilemmoma
  • Papillomatosis in the mouth
  • A family history of PTEN gene mutation
  • A genetic test showing a PTEN gene mutation


After diagnosis, recommended treatment for Cowden syndrome focuses heavily on following a strict routine cancer screening schedule. This is because of the increased risk for developing certain types of cancers, beginning at the time of diagnosis and expanding as the person ages.

For people born with female biology, this may look something like:

  • Breast self-exams beginning at age 18
  • Breast clinical exams beginning at age 25
  • Annual mammogram beginning at age 30–35
  • Annual endometrial cancer ultrasound screening or random biopsy beginning at age 30–35

For all individuals, screenings may follow this timeline:

  • Annual physical examination beginning at age 18
  • Annual thyroid ultrasound beginning at age 18
  • Colonoscopy beginning at age 35
  • Kidney ultrasound beginning at age 40

Cancer Screening for Children

Children under the age of 18 with Cowden syndrome are recommended to get a yearly thyroid ultrasound, a yearly skin check and physical examination, and a neurodevelopment evaluation.

Other key treatment options for Cowden syndrome include:

  • Surgical procedures: Tumors may be removed if they are causing pain or discomfort, or if they're suspected to be cancerous. People born with female biology also may be candidates for preventive removal of the breasts or uterus, for example, before cancer can develop.
  • Dermatological treatment: Because the skin is affected in almost all Cowden syndrome cases, a dermatologist (a doctor specializing in skin, hair, and nails) may be helpful in identifying affected skin bumps and tumors, removing or treating them with laser resurfacing, and providing essential routine skin cancer screening.


With access to the necessary medical care and guidance, people with Cowden syndrome can absolutely lead healthy, productive lives.

Because Cowden syndrome is linked to an increased risk for developing multiple types of cancer, it's especially important to receive a timely diagnosis and close follow-up care. Early recognition of cancer development can be lifesaving, as it's possible for cancers to be curable if they're detected early enough.

Patient education also is an important component when living with Cowden syndrome. Experts recommend that patients take part in learning about preventive tactics. These include living healthily, avoiding potential cancer-causing behaviors, and early detection by recognizing the red flag symptoms for related cancers.

These approaches can be helpful in managing overall care and quality of life for Cowden syndrome.


Cowden syndrome is a rare genetic condition that results in the growth of benign hamartoma tumors and an increased risk for certain types of cancer. Individuals may also have a larger head size and developmental or learning delays. Treatment includes screening for cancer so it may be caught early.

A Word From Verywell

There are many unknowns that come with a Cowden syndrome diagnosis, and this can undoubtedly lead to feelings of stress, frustration, anger, and fear.

But remember that researchers have made great strides in improving detection and treatment options for many types of cancers, including those cancers that commonly develop with Cowden syndrome.

As long as you have access to strict routine medical screening and do your part to live as healthfully as possible, the odds of catching a developing cancer early in its tracks can be on your side. Make sure to discuss with your doctor the specific cancer screening schedule that is best for your individual circumstance, and stick to it.

Don't be afraid to bring up any pain or discomfort you're feeling, either. In addition to providing the necessary treatment, your medical care team can also help provide access to resources for additional support systems, which many patients find extremely beneficial.

Check out the PTEN Hamartoma Tumor Syndrome Foundation, the National Institutes of Health's Genetic and Rare Diseases Information Center, and RareConnect social networking platform for more information on Cowden syndrome education, research, recommendations, and emotional support.

Frequently Asked Questions

Can a parent pass down a risk for hamartomas to their child?

Yes. Cowden syndrome is inherited through what’s known as the autosomal dominant inheritance pattern. This means that only one copy of a mutated gene (likely the PTEN gene) needs to be passed down from parent to child in order for Cowden syndrome to show up.

That said, it's also important to point out that sometimes genetic conditions like Cowden syndrome can result from a new mutation and occur in people without a family history of the mutated gene.

How rare is Cowden syndrome?

Cowden syndrome is fairly rare, though it’s likely underdiagnosed in the first place. Experts estimate that it affects about one in 200,000 people, but that number might be larger. Males and females are equally affected, as are people of all racial and ethnic groups.

What are the symptoms of Cowden syndrome?

The first symptom that many people with Cowden syndrome notice is the characteristic hamartomas (benign fatty tumors) on various parts of the body. A larger-than-average sized head or developmental delays may also be noticeable.

In addition, papillomatous papules (benign skin-colored bumps in the mouth) and trichilemmomas (benign hair follicle tumors) may also appear.

Is Cowden syndrome preventable?

While there's currently no cure for Cowden syndrome, it is possible to manage this condition with close medical monitoring to prevent cancer development. Experts recommend vigorous cancer screening schedules to monitor for both cancerous and noncancerous growths on the body.

This would typically include specialized screenings for breast, thyroid, and potentially endometrial cancer, along with a routine colonoscopy and kidney imaging.

Routine screening for patients diagnosed with Cowden syndrome should start immediately. People with a known family history of Cowden syndrome might consider surveillance as early as 10 years younger than the age of the relative's cancer diagnosis.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Cristina Mutchler
Cristina Mutchler is an award-winning journalist with more than a decade of experience in national media, specializing in health and wellness content.