Cowden Syndrome

Cowden syndrome (CS) is an autosomal dominant genodermatosis and represents one of the clinical disorders on the spectrum linked to the germline mutation in the phosphatase and tensin homolog gene (PTEN). Located on chromosome 10, the PTEN gene is a dual specificity phosphatase which plays various roles in cell migration, apoptosis, and all processes that are important in the regulation of normal cellular growth [1]. Mutations in PTEN have been associated with various other disorders including Bannayan-Riley-Ruvalcaba syndrome, Proteus syndrome, adult L’hermitte-Duclos disease, and autism-like disorders associated with macrocephaly [2]. Cowden syndrome was first described by in the 1960s in a case report involving a patient named Rachel Cowden who presented with multiple hamartomas, unusualcutaneous findings, abnormal CNS findings, and fibrocystic breast disease [3]. Years later, Weary et al further reported the existence of this disorder with the first case series involving five subjects with similar clinical findings [4]. The PTEN mutation was finally found to be the cause in 1996. Currently, the clinical definition of CS has not only been widened to include multiple hamartomas involving any and sometimes all of the three embryonic germ cell layers but also now incorporates the significant risk of developing breast and/or non-medullary thyroid malignancy [5].