Endometrial stromal sarcoma: clinicopathological and immunophenotypic study of 16 cases.

Purpose: Endometrial stromal sarcomas (ESSs) are rare tumors and are divided into two groups: low-grade endometrial stromal sarcoma (ESS-LG) and undifferentiated endometrial sarcoma (UES). The purpose of this study was to compare the clinicopathological features and immunophenotypes of ESS-LG and UES.

Methods: The authors evaluated 16 patients diagnosed with ESS at the Hyogo Cancer Center, reviewed their files and data, and performed an immunohistochemical study for oncogenic proteins (EGFR, PDGFR-α, and PDGFR-β) and cell cycle regulators (cyclin D1, cyclin E, p16(INK4a), p21(cip1), p27(kip1), and p53) to compare ESS-LG and UES using the World Health Organization (WHO) classification.

Results: Four cases (25 %) were classified as ESS-LGs and 12 (75 %) as UES. Patients with UES had a significantly worse overall survival than did those with ESS-LG (p = 0.0445). Although no ESS-LGs showed expression of p16(INK4a), 10 of 12 (83 %) UESs showed expression of p16(INK4a). UESs showed a trend toward higher expression of cyclin D1, p21(cip1), and p53 compared with ESS-LGs.

Conclusions: Our data emphasize the clinical importance of the WHO classification of 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.