A Case Report of High-Grade Endometrial Stromal Sarcoma: A Rare Cause of Abnormal Uterine Bleeding in a Young Woman

Pleomorphic high grade endometrial stromal sarcoma with YWHAE gene amplification may be a novel variant with poor prognosis

Endometrial stromal neoplasms are classified by the World Health Organization (WHO) into endometrial stromal nodule (ESN), low grade (LGESS), high grade (HGESS), and undifferentiated uterine sarcoma (UUS). HGESS is subclassified based on molecular findings, YWHAE or BCOR. The HGESS with YWHAE::NUTM2A/B (alias YWHAE::FAM22A/B) fusion usually have relatively monomorphic (as with most fusion-associated malignancies) rounded to epithelioid cells with eosinophilic cytoplasm, vesicular nuclei, nucleoli, and mitotic figures >10/10 HPF. We present a 66-year-old woman with post-menopausal bleeding found to have a heterogeneous solid-cystic uterine mass on CT who underwent total hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and pelvic lymph node dissection. A 15.0×9.0 cm variegated uterine mass with hemorrhage and necrosis was identified. Histologically, the tumor was hypercellular with haphazard fascicles, microcysts, and tongue-like destructive myometrial invasion. Tumor cells exhibited marked pleomorphism and high mitotic activity with atypical mitotic figures. There was extensive cyclin-D1 and subset CD10 immunopositivity. FISH showed YWHAE amplification but without rearrangement. Interestingly, we found only two other reported cases of pleomorphic HGESS with YWHAE gene amplification upon review of 259 cases from cBioPortal database, one of which was reported as carcinosarcoma with heterologous elements. Of note, all three YWHAE amplified cases were diagnosed at high-stage and succumbed to disease within six months. Our case appears to be the third case of YWHAE-amplified pleomorphic HGESS, possibly a new variant of uterine sarcoma with aggressive biologic behavior that needs further evaluation.

Endometrial stromal sarcoma in a 20-year-old woman

Endometrial stromal sarcoma (ESS) is an uncommon and challenging condition comprising 10% of all uterine sarcomas and found in women 42-58 years of age. ESS is difficult to diagnose in young women as it masquerades as a leiomyoma. We report this tumour in a 20-year-old woman presenting with heavy and prolonged menses and urinary retention. She was not sexually active and did not give consent for pelvic examination. A preoperative diagnosis of a submucous leiomyoma with an adnexal mass was made. At laparotomy, the leiomyoma was found to be wedged between the cervix and the vagina, and was removed vaginally. A 5-6 cm retroperitoneal mass was adherent to the right pelvic wall, which was also removed. Histopathology of both specimens revealed ESS. The final diagnosis according to the International Federation of Gynaecology and Obstetrics classification was stage IV ESS. After oncology consult, she was referred for chemotherapy. She is now on follow-up.