Hamartomatous Polyposis Syndromes
Cowden's syndrome affects 1 in 200,000 patients and the hamartomatous polyps arise commonly from ectodermal and/or endodermal elements. The most important hamartomas include fibrocystic disease of the breast, thyroid goiters or adenomas, multiple polyposis of the gastrointestinal tract, and ovarian cysts. Up to 80% of these patients present dermatologic manifestations, such as trichellemomas or oral papillomas. Approximately 40% have macrocephaly. Breast cancer is the most serious complication of Cowden's syndrome and effects 33% of patients. Thyroid cancer affects about 10% of patients.
A clinical diagnosis can be established when an individual meets any of the following pathognomonic criteria: six or more facial papules of which three or more must be trichilemmomas; cutaneous facial papules and oral mucosal papillomatosis; oral mucosal papillomatosis and acral keratoses; or six or more palmo-plantar keratoses. A diagnosis is also made with: two major criteria (one of them being macrocephaly or Lhermitte Duclos disease); one major criteria and three minor criteria; or four minor criteria.
Genetic testing and Cowden's syndrome
PTEN mutations are responsible for 80% of Cowden's cases. PTEN is a tumor suppressor gene located in chromosome 10q22 involved in cell growth inhibition. When patients fulfill the above criteria, they should undergo PTEN gene testing.
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