Endometriosis is defined as the presence of endometrial glands and stroma outside of the uterine cavity that can lead to pelvic pain and infertility (1). Clinical histories consistent with endometriosis can be found dating back to the 17th and 18th centuries (2). In 1899, Russel first described and illustrated the presence of endometrial tissue within an ovary (3). In 1921, Sampson published his first case series of 23 patients with ovarian endometriomas and posited the theory of retrograde menstruation (4). Endometriosis affects up to 10%-15% of women of reproductive age (1). Despite this prevalence and ongoing research efforts, much about endometriosis remains an enigma, including its variability in symptoms and progression of disease, underlying pain mechanisms, effect on fertility, and response to treatment.
After more than one hundred years of experience with endometriosis, why do we understand so little? To move the field forward, perhaps it's time to take a step back, pause, and reconsider critical issues related to endometriosis.
What's in a name?
In medical school, we are taught the "classic" phenotype of endometriosis--early onset of severe menstrual period pain (dysmenorrhea) that often progresses to include noncyclic pain--as well as the 3 "dys's," i.e., dyschezia (pain when defecating that may be accompanied by changes in frequency of bowel movement), dyspareunia (persistent or recurrent vaginal pain that occurs during or after intercourse), and dysuria (pain associated with urination) (1). These symptoms characterize many women with endometriosis, but teaching this narrow clinical presentation alone is woefully inadequate and a disservice to our patients. I, too, was taught this dictum, but after years of treating patients with endometriosis, I have learned that endometriosis presents in any way it wants --with any degree, character, type, or location of pain. Patients with endometriosis may present with no pain at all, at any point in the reproductive age spectrum, with or without preceding symptoms, and may have only nongynecologic symptoms.
Conversely, not all pelvic pain indicates endometriosis or is even gynecologic. To assume that all women with this classic phenotype have endometriosis and then to aggressively and narrowly treat them without considering other etiologies is another grave disservice. We need to approach these patients with the knowledge that there are multifactorial etiologies of pelvic pain including, but not limited to, functional bowel disorders, pelvic floor dysfunction, interstitial cystitis, and neuropathic pain. Further, it is important to recognize and address the complex ways that mental illnesses, such as depression and anxiety, can affect the response to treatment of chronic pain (5). For providers who encounter women with pelvic pain, it is critical for timely diagnosis and management to consider gynecologic and nongynecologic causes as well...