Estrogen and progestogen receptor positive endometriotic lesions and disseminated cells in pelvic sentinel lymph nodes of patients with deep infiltrating rectovaginal endometriosis:: a pilot study

BACKGROUND: Deep infiltrating endometriosis (DIE) shows similarities to malignant diseases. A recent study involving DIE patients found endometriosis in mesorectal lymph nodes (LNs) after segmental bowel resection. However, it is unclear whether this observation is a local phenomenon or a sign of systemic disease. Therefore, we conducted a prospective study to investigate the occurrence of endometriosis in pelvic sentinel lymph nodes (SLNs) in patients with DIE. METHODS: Fourteen patients underwent primary surgery for symptomatic DIE. Combined vaginal laparoscopic-assisted resection of the rectovaginal septum was performed. Dye was injected into the visible/palpable nodule. SLNs were removed from the iliac region. In order to identify endometriotic cells, immunohistochemical analysis of estrogen and progestogen receptors, CD10 and cytokeratin was performed. RESULTS: In 12 out of 14 patients with DIE, SLNs were detected. The localization of the SLN followed the typical LN spread of the upper vagina. In three patients, we could detect typical endometriotic lesions in the LNs. Ten out of 12 (83.3%) SLNs showed disseminated estrogen and/or progestogen positive cells. CONCLUSIONS: By using immunohistochemistry, we could demonstrate endometriotic lesions and endometriotic-like cells in pelvic SLNs of patients with DIE suggesting the potential for lymphatic spread of the disease.