Endometrial stromal sarcoma resembling adenomyosis and menstrual-phase endometrium

Abstract Background. Low-grade endometrial stromal sarcoma (LGESS) and endometriosis are two conditions of different prognostic significance that are usually not difficult to distinguish histologically. Case. We present the case of a 38-year-old woman who underwent laparotomy after a diagnosis of endometrial stromal neoplasm on uterine curettings. Uterine enlargement and regional and paraaortic lymphadenopathy were found. Pathology showed adenomyotic-like myometrial hypertrophy and menstrual-like shedding of tumor in involved lymph nodes. The finding of large areas of endometrial stromal cells without accompanying glands forming tumorous masses in both sites supported the diagnosis of LGESS. We believe that this is the first time that these phenomena have been reported in LGESS. Conclusion. In these cases, adenomyotic myometrial hypertrophy and menstrual shedding have been used to distinguish endometriosis from LGESS, but do not appear to be absolute criteria. Endometriosis and LGESS are undoubtedly separate entities, but occasionally may resemble each other.