Cowden syndrome (CS) is a genetic condition that causes non-cancerous (benign) tumor-like growths and an increased risk of certain types of cancer. The growths, called hamartomas, are usually found on the skin, as well as in the nose and mouth. Cancers associated with CS are breast, uterus, and thyroid cancer. CS can also increase the risk for colon and rectum (colorectal) cancer, kidney cancer and skin cancer as well as a benign brain tumor called Lhermitte-Duclos disease. People with CS usually develop cancer in their 30s and 40s, which is earlier than most people develop cancer. Other symptoms of Cowden syndrome can include a large head (macrocephaly) and learning issues.
CS is caused by a change (mutation) in one of four different genes, including PTEN, SDHB, SDHD, and KLLN, which are all tumor suppressor genes. Tumor suppressors are involved in controlling cell growth. Typically, cells divide, grow, and die off in a controlled way. However, if a tumor suppressor gene is not working due to a mutation, it can cause a cell to divide faster than it should, leading to cancer. Mutations in the PTEN gene are the most common cause of CS. The condition is inherited in an autosomal dominant way, which means a mutation in only one of two copies of a gene that a person has is enough to cause the condition.
CS is typically suspected if a person has many hamartomas along with a personal or family history of a typical CS related cancer. Once a person is diagnosed with CS, cancer screenings (such as breast ultrasounds (mammograms) and blood tests), are usually recommended to find cancer in its early stages. If you or your child has been diagnosed with CS, talk with a doctor to decide on the best management options. Meeting with a genetic counselor may be helpful to better understand the risks of CS in your family. Support groups are available to connect with other families affected by CS.