Low-grade endometrial stromal sarcoma (LGESS) is a sarcoma of the uterus arising from endometrial stromal cells. It has an incidence of 0.3 cases per 100,000 people per year and accounts for less than 1% of uterine cancer. 1 It typically presents with abnormal uterine bleeding, pelvic pain or a pelvic mass. Microscopically, LGESS is characterised by tongues of bland cells resembling proliferative-phase endometrial stroma infiltrating into myometrium. Prominent lymphovascular invasion is common. Mitotic counts are generally low. Smooth muscle, sex cord like, myxoid, fibroblastic and glandular differentiation can occur. 2 The majority of LGESS have a gene rearrangement involving the polycomb complex, the most common being the JAZF1-SUZ12 fusion. The JAZF1-PHF1 fusion is the second most common rearrangement observed in 28% of LGESS.
Hatton et al. (Sun,) studied this question.