Occult endometrial cancer is occasionally discovered in women with Lynch syndrome undergoing risk-reducing hysterectomy. The case presented here demonstrates that preoperative endometrial sampling can help detect these occult cancers; however, there are currently no recommendations for this preoperative intervention. A 50-year-old woman with Lynch syndrome underwent endometrial sampling prior to planned risk-reducing hysterectomy and bilateral salpingo-oophorectomy. The endometrial biopsy demonstrated a serous endometrial cancer. The patient was counselled regarding the diagnosis and revised operative plan, which now included staging, prior to surgery. Although the prevalence of occult endometrial cancer at the time of risk-reducing surgery in women with Lynch syndrome remains unknown, preoperative endometrial sampling may allow for improved patient counselling and surgical planning in this population, and can help avoid a subsequent surgery for staging.