The migrated tissue retains its character and changes with the fluctuations of the menstrual cycle, bleeding at the time of menstruation . The blood becomes trapped in cysts that can grow from the size of a pinhead to the size of a grapefruit. Symptoms of endometriosis can be absent or can include painful menstruation, severe abdominal or low back pain, painful intercourse, and rectal bleeding at the time of menstruation. The cause of endometriosis is unknown. One hypothesis is that the endometrial fragments move back up through the fallopian tubes rather than leaving the body with the menstrual flow.
Diagnosis is by pelvic examination or laparoscopy.
Treatment, which depends on the severity of the disease, may include a course of oral contraceptives, or danazol if the patient is trying to conceive. In severe cases surgical removal of the cysts or hysterectomy may be performed.