For example, just as sperm can travel through the uterus and out the tubes, so can tiny particles of blood from a menstrual period. Although there are other theories to explain endometriosis that occurs in areas of the body far away from the female organs, Sampson's theory is the best explanation thus far of how endometriosis occurs. As the implants grow and respond to hormonal stimulation, they can cause symptoms. Interestingly, endometriosis has been diagnosed in unusual locations like the knees, thumbs, thigh, vulva, lungs and liver, and has even been diagnosed in men receiving estrogen therapy.
Endometriosis is a sometimes bizarre disorder.
Some women have dozens of implants but never have symptoms, while others may have a few visible implants but have severe pain. We're not sure why this condition is so variable, or why only a few lesions can cause such severe pain. Endometriosis can cause pelvic pain. Many women with endometriosis report severe pain with intercourse or exercising, or pain with bowel movements. The pain may be dull and throbbing, or sharp and stabbing, or even a combination of both.