Abstract
CASE: Cowden syndrome is an autosomal-dominantly inherited rare condition caused by germline pathogenic variants of the PTEN gene. Multiple tumor development at a younger age in this syndrome may warrant different modalities of fertility preservation. Here we report that women with this syndrome gave successful live birth with frozen-thaw embryo transfer that was cryopreserved before the start of chemotherapy for breast cancer. This woman also suffered from endometrial cancer that developed during hormonal treatment with GnRH agonist and tamoxifen for breast cancer. The lesion was well controlled with oral MPA therapy and hysteroscopic resection. OUTCOME: She could receive fertility preservation for breast cancer and endometrial cancer before fertility treatment and pregnancy. CONCLUSION: This is the first report of live births after multiple fertility preservation therapy for metachronous breast and uterine cancer in Cowden syndrome. Appropriate genetic counseling may help the patient's decision making. The treatment plan should be discussed with diverse professionals such as oncologists, reproductive physicians, perinatologists, geneticists, and genetic counselors.