• PTEN;
  • Cowden syndrome;
  • Bannayan–Riley–Ruvalcaba syndrome;
  • Proteus syndrome;
  • juvenile polyposis;
  • Peutz–Jeghers syndrome;
  • hamartoma


The inherited hamartoma polyposis syndromes encompass several distinct clinical syndromes with different genetic bases, Cowden syndrome (CS), Bannayan–Riley–Ruvalcaba syndrome (BRRS), juvenile polyposis syndrome (JPS), and Peutz–Jeghers syndrome (PJS). Germline mutations in PTEN, encoding a tumor suppressor phosphatase on 10q23.3, is associated with 80% of CS and 60% of BRRS. JPS is caused by mutations in MADH4 and BMPR1A, encoding two members of the TGFB superfamily. Germline mutations in LKB1 (STK11) are associated with a subset of PJS. The number, distribution, and histologic type of polyps differ amongst these syndromes as do component cancer risks. While rare, usually asymptomatic, hamartomatous polyps are felt to be component to CS. Hamartomatous polyposis is usually prominent and symptomatic in BRRS. Polyposis, which can be quite symptomatic, is a cardinal component feature of PJS and JPS. Interestingly, glycogenic acanthosis of the esophagus is highly predictive of CS and the presence of PTEN mutation. PTEN mutation positive CS have been shown to be at increased risk of breast, thyroid, and endometrial cancer. PTEN mutation positive BRRS are at increased risk of at least breast cancer, possibly that of the thyroid as well. In contrast, JPS and PJS have increased risk of gastrointestinal cancers in particular. Thus, molecular-based diagnoses to differentiate each of these syndromes are important for medical management. © 2003 Wiley-Liss, Inc.