To present the clinical characteristics of pelvic or extra-pelvic endometriosis and explore the potential risk factors of pathogenesis and recurrence by comparing patients with endometriosis at different sites

Endometriosis is a chronic inflammatory disease defined as the presence of endometrial glands and stroma outside of the internal epithelial lining of the cavum uteri, affecting up to 10% of reproductive age women. It is rarely found in extrapelvic locations.This form of endometriosis may be difficult to diagnosis due to pleomorphic presentation. Despite complete excision with a safe margin and histopathological examination has been considered as definitive diagnosis and primary therapeutic treatment for extra-pelvic endometriosis, what is understood mainly comes from case reports and retrospective observations with limited number of cases. Moreover, approximately 6%-14% of patients with PEM who had underwent narrowly operative resection still suffered recurrent lesions, while risk factors were barely identified.

Patients with endometriosis at different sites in our hospital were collected for analysis of clinical characteristics namely demographic information, medical history, surgical records, pathological and imaging reports, serum levels of cancer antigen 125 (CA125), peri-operative medication. During long-term follow-up, prognosis of individuals could be identified by telephone or clinical interview. Based on data from medical records or clinical observation, risk model predicting recurrence will be established by comparing patients with different outcomes or exposed to different risk factors. Thus, management of endometriosis might be improved. Hopefully, pathogenesis of recurrent and primary endometriosis might be explained.

Inclusion Criteria:

• Patients who were clinically diagnosed with endometriosis at different sites (pelvic and/or extra-pelvic) and received surgical treatment at PUMCH

Exclusion Criteria:

• i). underwent bilateral oophorectomy in the operation, ii). had incomplete records of inpatient management, iii). had no post-operative outpatient follow-up, iv). combined with malignancy.

Women aged between 18 years old to 50 years old, who were diagnosed as endometriosis (both pelvic and extra-pelvic) and received surgical treatment in PUMCH.