Foreword

Endometriosis happens when endometrial tissue is discovered outside the uterine cavity.

Etiology

If endometrial tissue is discovered at the ovary, it is so-called endometrioma or chocolate cyst.If the endometriosis occurs in the myometrium, it is called adenomyosis. Even though the etiology of endometriosis is still unclear, hypotheses include:

1. Menstruation blood reflux: menstrual blood containing endometrial cells refluxes through ovarian tube into abdominal cavity.
2. transported by vascular and lymphatic systems: menstrual blood containing endometrial cells passes through orifices of uterine vascular and lymphatic vessels. It is transported to other parts of the body such as lung, umbilicus, and lymph nodes.
3. auto-immune deficiency: endometrial tissue can be degraded by phagocytosis of leukocyte and lymphocyte. However, there are a few women who could not absorb excessive endometrial tissue; so those cells would be attached to ovary, ovarian tube, urinary bladder, colon, and Douglas pouch.

Examinations

1. Palpation: colon and vagina digital examination or abdominal palpation
2. Ultrasonography: to detect the location of pelvic cyst
3. Blood examination: to examine the level of CA-125 tumor marker
4. Laparoscopic examination: the only means to confirm diagnosis

Symptoms

1. Dysmenorrhea: one to two weeks before menstrual period, most women often feel backache, diarrhea, dizziness, severe abdominal pain, and dropping feeling of lower abdomen. 
2. Infertility: there are 30%-50% of women are infertile because they have endometriosis.
3. Dyspareunia: there are 25%-40% of women suffering from painful sexual intercourse.
4. hypermenorrhea or vaginal spotting before menstrual cycle: there are about 20% to 30% abnormal vaginal bleeding incurred by hormonal dysfunction.
5. Surgical scar tissue with periodical pain: when there is endometriosis incurred by surgical scar, patients would suffer from pain caused by menstrual period. 
6. periodical hemoptysis and epistaxis: endometriosis invading nasal mucosa and lung.
7. others: there are also non-specific symptoms such as hematuria, dysuria, and anal pain caused by defecation.

Treatments

1. Hormone therapy like progesterone, oral contraceptives, and androgen
2. Surgical treatments including laparoscopic or laparotomy surgery
3. Combined medical and surgical treatment