A 6.3 kg uterine tumor resembling an ovarian sex cord-stromal tumor (UTROSCT): A case report.

Uterine tumor resembling ovarian sex cord-stromal tumor (UTROSCT) is a rare uterine neoplasm characterized by sex cord-like differentiation. Although typically indolent and confined to the uterus, UTROSCT can occasionally exhibit atypical clinical and pathological behavior, complicating preoperative diagnosis. A 52-year-old postmenopausal woman (G3P3A0) with no significant medical history presented with a painless umbilical swelling persisting for eight months. Physical and radiological assessment revealed a paraumbilical hernia and she was scheduled for elective laparoscopic repair. Intraoperatively, a large amount of viscous gelatinous material was unexpectedly discovered in the peritoneal cavity, with no visible peritoneal or visceral mass. Peritoneal biopsies and cytology suggested a low-grade neoplasm of uncertain origin, initially raising suspicion of pseudomyxoma peritonei (PMP). Computed tomography showed a large soft-tissue lesion occupying the lower abdomen and pelvic cavity, extending to the umbilicus and supplied by a branch of the uterine artery. Multidisciplinary tumor board discussion favored a uterine source, and cytoreductive surgery with total hysterectomy and peritonectomy was performed. A 40 cm encapsulated gelatinous uterine mass weighing 6.3 kg was excised. Histopathology and immunohistochemistry confirmed UTROSCT with positivity for sex cord markers and hormone receptors. Margins were negative and there was no lymphovascular invasion. The postoperative course was uneventful. The patient received adjuvant tamoxifen therapy and remained disease-free during 48 months of follow-up. This case illustrates an exceedingly rare presentation of UTROSCT, with much large tumor size than previously reported.