Low-grade endometrial stromal sarcoma and undifferentiated endometrial sarcoma: a comparative analysis emphasizing...

Endometrial stromal sarcomas (ESSs) are rare tumors whose classification is still controversial. In this study, the authors studied 19 patients diagnosed with ESS at the Hospital S João, Porto, Portugal; reviewed their files and material; and performed immunohistochemical study for CD10, desmin, and smooth muscle actin markers, aiming to compare low-grade endometrial stromal sarcomas (LG-ESSs) and undifferentiated endometrial sarcomas (UESs) using the World Health Organization (WHO) classification. Twelve cases (63%) were classified as LG-ESS and 7 (37%) as UES. The median age at diagnosis was 49 years, and women with LG-ESS tended to be younger than those with UES. Most cases (7/11) had a previous echographic diagnosis of leiomyoma. A biopsy or curettage was performed in 6 cases, providing a definitive diagnosis of malignancy in 4. Frozen section was performed in 4 patients. The majority (63%) of patients were FIGO stage I. Twelve (63%) cases showed diffuse or focal expression of CD10. Desmin and smooth muscle actin expression was focal in 4 (21%) tumors. Patients with LG-ESS had a significant better overall survival than those with UES (P = .026). Mitotic count had no prognostic significance. Our data emphasize the clinical importance of the WHO classification in ESS. It is of utmost importance to establish a proper classification to increase the consistency of data that may be useful for improving clinical and therapeutic management of patients with ESS.