Definition:

Cowden syndrome (CS) is an autosomal dominant inherited cancer syndrome characterized by benign and malignant breast, thyroid, and endometrial neoplasias in addition to cutaneous findings and macrocephaly. Germ line PTEN mutations have been found in 85% of those with CS. A large heterogeneous group of individuals with Cowden-like syndrome, who have various combinations of Cowden syndrome features but who do not meet Cowden syndrome diagnostic criteria, have PTEN mutations less than 10% of the time. In the absence of germline PTEN mutations, approximately 10% of individuals with Cowden syndrome or Cowden-like syndrome harbor germline succinate dehydrogenase variants SDHB and SDHD.