Extrapelvic Endometriosis

“Few problems in the field of medicine test the diagnostic and therapeutic judgment of the surgeon more fully than endometriosis …It is unfortunate that despite extensive investigations the complex nature of this disease is still not fully understood.”52 “Endometriosis is … among the most enigmatic of gynecologic diseases. The literature on endometriosis isextensive, though often contradictory or inadequate …”98 The above statements, written by endometriosis researchers 40 years apart, reflect a continued frustration with the lack of progress in understanding this common condition. Researchers are even uncertain as to the precise definition; classically, endometriosis is defined as “the presence of endometrial glands and stroma outside the uterine cavity and musculature,”98 although some definitions specify that the ectopic tissue must be functional.75, 119 In addition, endometriosis was originally described as two variants, endometriosis interna and endometriosis externa. Endometriosis interna, now referred to as adenomyosis, describes growth of benign endometrial tissue into the myometrium, whereas endometriosis externa is the presence of endometrial tissue implants in all other sites, whether physically proximal to the uterus (e.g., the fallopian tubes and ovaries) or in sites as remote as the brain.27, 57, 140 It is clear now that the epidemiology, pathogenesis, diagnosis, and natural history of endometriosis interna differ from those of endometriosis externa98; however, it is not clear whether endometriosis externa occurring in sites far from the pelvis is the same disease and can be treated with the same modalities and success as pelvic endometriosis externa.78 As enigmatic as pelvic endometriosis has proven to be, extrapelvic endometriosis is unquestionably more rare, more difficult to diagnose and treat, and has certainly been less well studied.13, 143 This review describes and critically evaluates the theories of the pathogenesis of extrapelvic endometriosis, as well as studies of its epidemiology, diagnosis, and treatment. In this review, as in earlier articles,13, 78 pelvic endometriosis is defined as lesions of the fallopian tubes, ovaries, and local peritoneum. Extrapelvic endometriosis refers to endometriotic implants found elsewhere in the body, including the gastrointestinal tract, urinary tract, pulmonary system, extremities, skin, and central nervous system (CNS).