Cowden Syndrome

• Cowden syndrome is caused by a mutation in the PTEN gene.

  • It is one of the few breast cancer predisposition syndromes with a clinically recognizable phenotype (Peutz-Jeghers syndrome is another).

• Clinical features include extreme macrocephaly (head circumference >60 cm in a woman), multiple facial tricholemmomas (small skin-colored papules) and a family history of thyroid cancer before age 20 years or endometrial cancer before age 30 years.

• It is a very rare syndrome, with only six cases identified among 2079 recently reported multigene panel tests.

• It is clinically important, however, because the lifetime breast cancer risk may be as high as 85% and affected individuals have a very high risk of endometrial and thyroid cancer as well as a moderately increased risk of colorectal cancer and melanoma.

• Current American Cancer Society guidelines support enhanced surveillance with annual mammogram and magnetic resonance imaging for women with PTEN mutations, though the timing of when this should begin is vague.

  • Data by Riegert-Johnson et al. suggest screening should commence around age 30 to 35 years as this is the time that the risk of breast cancer starts to increase.

  • Even after a cancer diagnosis, individuals with Cowden syndrome remain at increased risk of a variety of second primary cancers, especially breast, thyroid, and endometrial.

REFERENCES

1. LaDuca H, Stuenkel AJ, Dolinsky JS, et al. Utilization of multigene panels in hereditary cancer predisposition testing: analysis of more than 2,000 patients. Genet Med. 2014;16:830-837.
2. Ngeow J, Stanuch K, Mester JL, et al. Second malignant neoplasms in patients with Cowden syndrome with underlying germline PTEN mutations. J Clin Oncol. 2014;32:1818-1824.
3. Riegert-Johnson DL, Gleeson FC, Roberts M, et al. Cancer and Lhermitte-Duclos disease are common in Cowden syndrome patients. Hered Cancer Clin Pract. 2010;8:6.
4. Tan MH, Mester JL, Ngeow J, et al. Lifetime cancer risks in individuals with germline PTEN mutations. Clin Cancer Res. 2012;18:400-407.