Incidental endometrial cancer diagnosis during pre-IVF workup: fertility-sparing treatment and embryo preservation.

We report the incidental diagnosis of endometrial cancer in a 42-year-old nulliparous woman undergoing routine fertility workup. During pre-in vitro fertilization (IVF) saline hysterosonography (HSN), a small (<1 cm) endometrial polyp at the fundus was identified and removed hysteroscopically. Initial histologic examination performed outside the United States demonstrated a grade 2 endometrioid carcinoma. The hysteroscopic pathology slides were subsequently reviewed in the United States, and the diagnosis was revised to grade 1, stage IA endometrioid carcinoma confined to the endometrium. Staging magnetic resonance imaging showed no myometrial invasion or metastatic disease, supporting a fertility-sparing management approach. Before initiating high-dose progestin therapy, the patient underwent fertility-preserving ovarian stimulation with a letrozole-based gonadotropin-releasing hormone antagonist protocol. This cycle yielded 4 embryos for cryopreservation. Had she proceeded with her planned IVF cycle before endometrial lesion was assessed, ovarian stimulation might have accelerated an undiagnosed estrogen-dependent malignancy. This case underscores the value of comprehensive pre-IVF diagnostic evaluation, through which incidentally detected early-stage endometrial carcinoma can be identified before ovarian stimulation and embryo transfer. It also highlights a potential role for fertility preservation in selected reproductive-aged patients and emphasizes the importance of guideline-based fertility-sparing management in estrogen-dependent gynecologic cancers.