Uterine Tumor Resembling Ovarian Sex Cord Tumor (UTROSCT) With a GREB1-NCOA2 Fusion: A Case Report and Diagnostic Considerations.

Uterine Tumor Resembling Ovarian Sex Cord Tumor (UTROSCT) is a rare mesenchymal neoplasm with uncertain malignant potential. We report a 37-year-old woman with menorrhagia, initially suspected as a leiomyoma on MRI. Hysteroscopic resection revealed an infiltrative tumor with cords, glands, and spindle cells showing mild-to-moderate atypia. Immunohistochemistry was positive for ER, PR, WT-1, Calretinin, and FOXL2. RNA-based NGS identified the GREB1-NCOA2 fusion. Despite treatment, the patient died from metastases within 24 months. This case highlights UTROSCT's aggressive potential in young patients and underscores the diagnostic utility of molecular testing (e.g., GREB1 rearrangements) to distinguish it from mimics like LG-ESS. The fatal outcome suggests GREB1-NCOA2 may correlate with high-risk behavior, warranting close follow-up.