Primary peritoneal cancer after bilateral salpingo-oophorectomy in two patients with lynch syndrome

Backgrond: Women with Lynch syndrome or hereditary nonpolyposis colorectal carcinoma (HNPCC) have a 40-60% lifetime risk of endometrial cancer and a 7-12% lifetime risk of ovarian cancer. Risk-reducing surgery, including hysterectomy and bilateral salpingo-oophorectomy (BSO), is currently recommended once child bearing is complete. We describe two cases of primary peritoneal cancer after BSO in women with Lynch syndrome or HNPCC. Cases: The first patient was a 44-year-old woman who underwent hysterectomy with BSO for benign disease. She presented 12 years later with a pelvic mass and was diagnosed with a high-grade serous primary peritoneal cancer. Genetic testing showed a mutation in the MSH2 DNA mismatch repair gene. The second case was a 58-year-old woman who had a hysterectomy and BSO for endometrial cancer. She developed a high-grade serous primary peritoneal cancer 8 years later and was found to have a mutation in the PMS2 DNA mismatch repair gene. Conclusion: Women with Lynch syndrome or HNPCC should be counseled that they may be at risk for developing primary peritoneal cancer despite undergoing gynecologic cancer risk-reducing surgery. The magnitude of this risk remains to be determined.