Lymphatic spread of endometriosis to pelvic sentinel lymph nodes: a prospective clinical study

ObjectiveTo establish the prevalence of endometriosis metastatic to pelvic sentinel lymph nodes (PSLN) in women with ovarian and/or peritoneal endometriosis.DesignProspective clinical study.SettingAcademic research institution.Patient(s)Women with a laparoscopic diagnosis of ovarian and/or peritoneal endometriosis verified by intraoperative frozen section analysis.Intervention(s)Resection of endometriotic lesions and PSLN after cervical blue dye injection.Main Outcome Measure(s)Histologic analysis of PSLN for the presence of endometriosis and immunohistochemical analysis of estrogen receptor (ER), progesterone receptor (PR), cytokeratin (CK), and CD-10 expression.Result(s)The study enrolled 26 women with suspected endometriosis; endometriosis was confirmed in 23 women, and a PSLN was identified in 19 women. A total of 37 (right side: 20; left side: 17) lymph nodes were removed. The prevalence of endometriotic lesions in PSLN was 11% (2 of 19). Both lesions were positive for ER, PR, CK, and CD-10. Isolated endometriotic-like cells (IELCs) staining positive for ER and PR were identified in the peripheral sinus of 16 (80%) of 20 and 14 (70%) of 20 PSLN, respectively. All IELCs lacked CK staining, whereas CD-10 staining was present in 16 (80%) of 20 cases, indicating a stromal origin of IELCs. Intraoperative and/or postoperative complications were observed in 1 (5%) of 19 women.Conclusion(s)Spread of IELCs to PSLN is common in ovarian and/or peritoneal endometriosis. Metastatic lesions in PSLN are present in 11% of women. Further studies to evaluate the prognostic and predictive value of endometriotic spread to PSLN are warranted.