Giant low-grade endometrial stromal sarcoma with extensive sex cord-like differentiation: a case report.

BACKGROUND: A low-grade endometrial stromal sarcoma (LG-ESS) is a rare uterine malignancy that can resemble benign conditions like leiomyoma or adenomyosis. Diagnosis is challenging, particularly when sex cord-like differentiation is present, which can mimic other uterine or ovarian tumors. CASE PRESENTATION: A 45-year-old woman presented with pelvic discomfort and heavy bleeding. Imaging suggested a 13-cm leiomyoma. She underwent a total hysterectomy with bilateral salpingo-oophorectomy. Histology showed classic LG-ESS features with extensive sex cord-like areas. Immunohistochemistry confirmed the presence of an LG-ESS (CD10+, ER+, inhibin+, and calretinin+). DISCUSSION: An extensive sex cord-like differentiation in an LG-ESS is rare and may lead to misdiagnosis. Accurate identification requires immunostaining to distinguish from mimics. Prognosis remains favorable with complete surgical resection. Ovarian removal was chosen due to the patient's age and tumor features. CONCLUSION: This case highlights a rare LG-ESS variant with unusual morphology, stressing the importance of histopathological evaluation and long-term follow-up to monitor for late recurrence.