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Cowden Syndrome

Cowden syndrome, also known as multiple hamartoma syndrome, is a rare genetic condition that increases the risk of certain types of cancer. It is caused by a mutation of the phosphatase and tensin homolog (PTEN) gene, which is a tumour suppressor gene. Cowden syndrome is the most common type of PTEN hamartoma syndrome.

Familial cancer syndromes, also known as hereditary cancer syndromes, are rare conditions that cause an increased risk of cancer as the result of inherited genetic mutations in certain cancer-related genes. They can affect both adults and children, however they generally develop in people at a younger age than normal. While familial cancer syndromes are not classified as cancer, they are equally as severe and can be life-threatening as they are associated with the development of various tumours throughout the body. Having a familial cancer syndrome does not guarantee the development of cancer, however the risk of developing cancer is higher than those who do not have a familial cancer syndrome.

Cowden syndrome tends to affect the sexes equally, and is generally diagnosed between the ages of 30-40. However, anyone can develop this disease.

Cowden syndrome is most commonly associated with the development of hamartomas, however it has also been linked to other types of tumours. Some examples include:

Treatment

When cancers are detected, they are staged and graded based on size, metastasis, and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you. However, each patient with Cowden syndrome will present with a unique disease behaviour, with varying tumour locations and symptoms. As such, there is no one treatment method that will work for everyone, and there is no standard staging system for this disease. Instead of staging and grading, your doctor will recommend a treatment plan based on the following factors:

  • Type of tumours present.
  • Whether the tumours are malignant (cancerous) or benign (non-cancerous).
  • Tumour location.
  • Whether or not malignant tumours have metastasised.
  • Your age.
  • General health.
  • Your treatment preferences.

Your doctor may also recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.

Treatment options for tumours associated with Cowden syndrome may include:

  • Surgery to remove as much of the tumour(s) as possible – these will vary based on tumour type and location.
  • Chemotherapy.
  • Radiation therapy.
  • Clinical trials.
  • Palliative care.

Cancer Screening

Once a diagnosis of Cowden syndrome has been confirmed, implementing a targeted screening plan becomes essential due to the increased risk of developing certain cancers.  The content of this plan will vary from person to person based on the genetic mutation involved, your family’s history of cancer and the types of cancers that may be present. It will also outline the routine tests you should have and how regularly you should have them.  Some recommendations for Cowden syndrome may include:

  • Annual physical exam starting at age 18 or five years before the earliest known cancer in the family was diagnosed (whichever comes first).
  • Annual breast mammogram and/or breast MRI starting at age 30 or 10 years before the earliest known breast cancer in the family was diagnosed (whichever comes first).
  • Colonoscopy every five years starting at age 35 or 5-10 years before the earliest known colon cancer in the family was diagnosed (whichever comes first).
  • Annual skin examinations.
  • Annual thyroid ultrasounds starting at age seven.
  • Consideration of endometrial screening at age 35 in females.
  • Consideration of renal ultrasound at age 40, then every 1-2 years.

Screening options for Cowden syndrome may evolve as new technologies are developed and our understanding of the condition grows. It is essential to discuss your individual circumstances with your healthcare team to determine the most appropriate screening plan for you.

Risk factors

Cowden syndrome is caused by a genetic mutation of the phosphatase and tensin homolog (PTEN) gene, which is a type of tumour suppressor gene. Two other genes, KLLN and WWP1, may also cause Cowden syndrome in some families. Cowden syndrome is an autosomal dominant disorder, which means that you have a 50% chance of developing the condition if one of your parents carries the mutation.

Symptoms

The symptoms of Cowden syndrome often vary by the type(s) of tumours present. General symptoms of Cowden syndrome may include:

  • Hamartomas.
  • Trichilemmomas (benign, wart-like growths that start in the hair follicles).
  • Oral papules or fibromas.
  • Keratoses on the surfaces of the hands and feet.
  • Macrocephaly (abnormally large head).
  • Intellectual disability.
  • Autism spectrum disorder.
  • Thyroid abnormalities, such as benign tumours and goitres.
  • Testicular lipomatosis.
  • Lipomas.
  • Polyps in the gastrointestinal tract.
  • Fibromas.

Symptoms related to specific tumours can be found on our knowledgebase.

Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.

Diagnosis

If your doctor suspects you have tumours associated with Cowden syndrome, they may order some of the following tests to confirm the diagnosis and refer you to a specialist for treatment. The tests required for diagnosis will often vary based on the symptoms present, and where the tumour(s) are suspected to be located.

  • Physical examination.
  • Neurological examination.
  • Pelvic examination.
  • Blood tests.
  • Imaging tests, potentially including:
    • Mammogram.
    • MRI (magnetic resonance imaging).
    • Ultrasound.
  • Exploratory procedures, such as an endoscopy.
  • Biopsy.

References

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