Cowden syndrome is an autosomal dominant disease with characteristic mucocutaneous lesions, macrocephaly, polyposis gastrointestinal (GI) tract, and an increased risk of thyroid tumors, particularly follicular, breast and endometrium. The risk of tumors of the digestive tract is slightly elevated.
However, there may other types of tumors and vascular malformations. The cause is usually a mutation in PTEN.