Characteristics and location of extrapelvic endometriosis

Characteristics and location of extrapelvic endometriosis

Out of 1000 women with endometriosis, 200 presented extrapelvic endometriosis with gastrointestinal tract being the most common location of endometriotic implants.

Key Points


  • About 20% of the women with endometriosis involved in this study showed extrapelvic endometriosis.
  • The gastrointestinal tract was the most common location of extrapelvic endometriosis followed by the urinary system.
  • No significant variations in demographic, menstrual and reproductive characteristics in women with pelvic and extrapelvic endometriosis were observed.


  • Currently, the exact prevalence of extrapelvic endometriosis is unknown because well-designed epidemiological studies are lacking. This study, although retrospective, includes a significant number of women with endometriosis and indicates the magnitude of extrapelvic endometriosis cases. 
  • This is the first extensive report that investigates the anatomical distribution of extrapelvic endometriosis.

What’s done here?

  • This is a retrospective review of medical records of 1000 women with endometriosis from the United States and Greece to assess the characteristics of extrapelvic endometriosis versus pelvic endometriosis and to determine common locations for extrapelvic endometriosis.

Key results:

  • The gastrointestinal tract was the major location of extrapelvic endometriosis, with 52% of the cases presented digestive tract implants. The sigmoid colon was mostly involved, followed by the rectum, ileum, and the appendix.
  • The urinary system was the second most common site, with 35% of the cases involving urinary tract endometriosis.
  • Of the 200 women with extrapelvic endometriosis, 155 also had pelvic endometriosis.
  • Women with pelvic and extrapelvic endometriosis share similar characteristics such as age, weight, chief complaints, stage of endometriosis, and family history of endometriosis.

Limitations of the study:

This is a retrospective study prone to selection bias and misclassifications. It relies on information gathered by other investigators/clinicians.

Lay Summary

The authors of this study reviewed the medical records of 1000 women with endometriosis from two geographical areas, New Haven, US and Crete, Greece over a 20-year period with a goal of identifying the presence and location of extrapelvic endometriosis and its associated characteristics. Extrapelvic endometriosis refers to the endometriotic tissue attached to the areas other than uterus-proximal locations such as ovaries, fallopian tubes, uterine ligaments and the surrounding pelvic peritoneum.

Of the 1000 women studied, 200 cases were identified with extrapelvic endometriosis. The gastrointestinal tract represented the most common site of extrapelvic endometriosis with 104/200 (52%) cases, followed by the urinary tract with 70/200 (35%) cases. Interestingly, 155/200 (77.5%) of women with extrapelvic endometriosis also had pelvic endometriosis. All 1000 women regardless of having pelvic or extrapelvic endometriosis showed similar characteristics involving age, weight, chief complaints, and family history of endometriosis. However, extrapelvic endometriosis patients were predominantly stages III and IV endometriosis.

Currently, the mechanisms leading to the development of extrapelvic lesions are unknown, although the involvement of several factors including unknown familial susceptibility, immunological or genetic factors implicated. Of those, two proteins – the vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2) – were previously examined in extrapelvic endometriosis lesions and their involvement in the pathogenesis of extrapelvic endometriosis was suggested. However, further research and more studies are required to understand the mechanisms causing extrapelvic endometriosis.

Research Source:

extrapelvic endometriosis gastrointestinal tract urinary system


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