Management and outcomes of fertility preservation in rare Cowden syndrome-associated endometrial carcinoma: a case series

BACKGROUND: Cowden syndrome-associated endometrial carcinoma (CS-EC) is rare, and data on fertility-preserving treatment for young patients remain limited. This series describes the diagnosis and management of three patients with CS-EC who underwent fertility-sparing treatment. We also report the subsequent pregnancy outcome for one of these individuals. These cases provide a clinical reference for the individualized management of such patients. CASE PRESENTATION: Three patients (aged 29, 31, and 28 years) with germline Phosphatase and tensin homolog (PTEN) pathogenic variants and stage IA endometrial carcinoma underwent individualized fertility-sparing treatment. Case 1 (PTEN p.R189Qfs*9) failed levonorgestrel-releasing intrauterine system (LNG-IUS) treatment at 19 months. Eight cycles of GnRH agonist (GnRH-a) plus letrozole (LE) subsequently induced a complete response. A recurrence was successfully managed with twelve additional cycles of this regimen. Case 2 (PTEN p.R173C) attained remission after six months of megestrol acetate (MA). Case 3 (PTEN p.R335*) responded to MA over nine months, then developed complex mucinous papillary metaplasia during LNG-IUS maintenance, which resolved with ethinylestradiol/cyproterone acetate (EE/CPA). She subsequently conceived and delivered a live birth through Intracytoplasmic sperm injection (ICSI). During the follow-up period, all patients were administered maintenance therapy using a LNG-IUD. CONCLUSIONS: Fertility-sparing therapy may serve as a potentially feasible option for highly selected patients with stage IA CS-EC, and could lead to relatively favorable pregnancy outcomes. The clinical feasibility of this strategy relies heavily on strict patient selection, timely molecular diagnosis, and standardized continuous multidisciplinary management.