Endometriosis is common among women of reproductive age, and its prevalence increases to 30-40% among infertile women. Clinical findings vary greatly depending on the number, size, and extent of the lesions and on the patient population being examined.

The diagnosis of endometriosis is often strongly suspected from a patient’s initial history. Infertility, dysmenorrhea and dyspareunia are the main presenting complaints. Most patients complain of constant pelvic pain or a low sacral backache that occurs premenstrually and subsides after menses begins. Dyspareunia is often present, particularly with deep penetration. Lesions involving the urinary tract or bowel may result in bloody urine or stool in the perimenstrual interval. Implantations on or near the external surfaces of the cervix, vagina, vulva, rectum, or urethra may cause pain or bleeding with defecation, urination, or intercourse at any time in the menstrual cycle. Adhesions from endometriosis may cause discomfort at any time during the cycle, and a sensation of pelvic pressure may result if large masses are present. Premenstrual spotting may occur and is more likely to be associated with endometriosis than with luteal phase inadequacy. It must be emphasized, however, that many patients either have no symptoms or have infertility as their only symptom and that the extent of disease often has little correlation with the severity of symptoms.

The physical examination may also be helpful in discerning whether endometriosis is present. Classically, pelvic examination reveals tender nodules in the posterior vaginal fornix and pain upon uterine motion. The uterus may be fixed and retroverted due to cul-de-sac adhesions, and tender adnexal masses may be felt because of the presence of endometriomas. Careful inspection may reveal implants in healed wounds, especially episiotomy and cesarean section incisions, in the vaginal fornix, or on the cervix. Biopsy may be required to prove that the lesions are due to endometriosis. However, many patients have no abnormal findings on physical examination.

For the vast majority of patients, endometriosis is included in the differential diagnosis of infertility or pelvic pain. Endometriosis should be suspected in any patient of reproductive age complaining of pain or infertility. Medical treatment can be given for pelvic pain thought to be due to endometriosis, but the specific diagnosis of endometriosis should not be made unless documented by direct visualization. The final diagnosis of endometriosis can only be made at laparoscopy or laparotomy, by direct observation of the implants. Occasionally, an isolated endometrioma is removed, and the diagnosis must be made histologically by the demonstration of “endometrial” glands and stroma or of hemosiderin-laden macrophages in the cyst wall.

Except for special circumstances, such as urography or sigmoidoscopy for suspected bowel or urinary involvement, ancillary diagnostic studies (ultrasound, x-rays, CT scans) are of little help in diagnosis.