Diagnostic Dilemmas in Endometriosis

Robert W. Kistner, M.D.
Assistant Professor of Obstetrics and Gynecology, Harvard Medical School, Boston; Associate Chief of Staff, Boston Hospital for Women, Parkway Division, Boston.

Endometriosis, Aspects and Proceedings of a Symposium
Saint John's Hospital and Health Center, Santa Monica, California
Editor: J.J. Marik

The diagnosis of endometriosis should be suspected by the history, corroborated by pelvic examination, and verified by endoscopy or biopsy. One should be able to suspect the disease process by pelvic examination, particularly by rectovaginal examination and finding tender, nodular uterosacral ligaments with a fixed third-degree uterine retroversion.

Remember, however, endometriosis is not the result of the third-degree retroversion; rather, endometriosis is its cause.

Obviously, this disease may be diagnosed by biopsy or endoscopy. In certain patients where there is a contraindication to laparoscopy, culdoscopy can be done by careful manipulation through the cul-de-sac.

The differential diagnosis of endometriosis involves excluding such diverse lesions as benign ovarian cyst, adenomyosis, ovarian cancer, pelvic inflammatory disease, metastatic bowel or ovarian cancer in the cul-de-sac, disseminated splenosis, and calcified mesotheliomas.

Benign ovarian cysts may persist for several months and bleeding from a corpus luteum cyst or adhesions around a follicle cyst may produce pelvic pain. These physiologic cysts are usually asymptomatic, but in certain patients they may be confused with endometriosis.

Similarly, adenomyosis may cause abnormal bleeding and pain. Ovarian and bowel cancer may produce nodularities in the cul-de-sac. Pelvic inflammatory disease may lead to bilateral tubo-ovarian masses and pain. Rarely, a ruptured spleen, calcified mesothelioma, or oxyuris vermicularis may produce calcified cul-de-sac nodules.

The differential diagnosis of ovarian endometriosis is occasionally difficult because of the presence of other diseases involving the uterus, tubes or ovaries. One patient, for example, a 44-year-old para 4 who had her last child at age 28 and had been asymptomatic until three months prior to surgery, noticed irregular bleeding and spotting with a dull aching pain in the right lower abdominal area. On pelvic examination, nodularity was felt in the cul-de-sac and both ovaries were enlarged and tender.

Laparotomy disclosed a large corpus luteum cyst and a follicle cyst of the left ovary, together with moderate ovarian endometriosis, and a total hysterectomy and bilateral salpingo-oophorectomy were performed. The irregular bleeding was undoubtedly due to the persistent and irregular production of estrogen and progesterone from the corpus luteum cyst.

The scattered areas of endometriosis on the ovary in this patient produced no symptoms, which is not unusual. Those patients who have the most extensive endometriosis have very little pain, while those who have minimal subperitoneal cul-de-sac endometriosis may suffer from severe pelvic pain.

It is important to remember, however, that every chocolate cyst of the ovary is not produced by endometriosis, since hemorrhagic follicle and corpora lutea cysts may have a similar gross appearance.

Incidentally, in this case, the gynecologist made a diagnosis of bilateral endometriomas prior to surgery on the basis of the history and the cul-de-sac nodules. The diagnosis was incorrect, but sufficient endometriosis was present to warrant hysterectomy and bilateral salpingo-oophorectomy.

Adenomyosis, or internal endometriosis, refers to the invasion and growth of endometrium in the myometrium and is usually characterized by a clinical situation quite different from that of external endometriosis. However, in certain conditions the symptoms may be quite similar in that pelvic pain, hypermenorrhea, and intermittent staining are common in both processes. Therefore, it merits consideration in differential diagnosis.

Adenomyosis usually occurs in an older age group than does endometriosis-about ages 35 through 50. The past history is usually that of increasing pelvic pain and hypermenorrhea in a woman of moderate parity. The adenomyotic uterus is symmetrically enlarged, nodular and tender, but the cul-de-sac and ovaries are usually normal.

Ovarian carcinoma is difficult to diagnose, due to the lack of specific symptoms. It is very important to note, therefore, the significance of endoscopy in making a precise diagnosis in infertile patients suspected of having ovarian endometriosis. Although carcinoma of the ovary does not arise frequently in areas of endometriosis, some authors have suggested that it occurs more often than is generally reported. If endoscopy is not used early in such cases, the endometriotic component may have been replaced by cancer by the time a definitive diagnosis can be made.

In patients with a previous history of ovarian endometriosis and infertility, the gynecologist must be aware of the possibility of malignancy occurring in such cases, and the patient should be so informed preoperatively. It should also be noted that patients with a proven history of endometriosis should have a pelvic examination every six months and endoscopy early in the infertility survey.

Differential diagnosis in patients with ovarian enlargement can also be very difficult. One patient, a 42-year-old para 2, complained of recurrent pelvic pain, and examination revealed a large left ovarian mass with displacement of the uterus. A diagnosis of endometriosis was made, but at laparotomy a large dermoid cyst of the ovary was found. An intraligamentous leiomyoma was also found together with endometriosis of the right ovary and surface of the uterus.

This illustrates the varieties of pelvic pathology which may coexist with endometriosis and which determine the type of surgical procedures performed, although it should be noted that the combination of benign cystic teratoma with ovarian endometriosis is not common.

Because of its frequency and variable clinical picture, the condition most frequently confused with endometriosis is chronic pelvic inflammatory disease with bilateral adherent adnexal masses. An inflammatory ovarian endometriotic cyst may present the same clinical picture as a tubo-ovarian abscess or pelvic abscess, and is rarely diagnosed prior to surgery.

It should also be borne in mind that rupture of an ovarian endometrial cyst may simulate pelvic peritonitis, appendicitis, ectopic pregnancy, ovarian cyst with twisted pedicle, rupture of a corpus luteum cyst or, in fact, any other acute pelvic condition.

One unusual condition which is impossible to differentiate from an ectopic pregnancy is a hematosalpinx resulting from endometriosis of the tuba) mucosa. Only microscopic examination will delineate trophoblastic tissue. If the pregnancy test is positive and hypersecretory glands are found in the endometrium, an ectopic pregnancy would be suspect.

Just as endosalpingiosis of the uterine corms develops in or near the transition from uterine to tuba) epithelium, endometriosis may also develop in the tubal mucosa near the fimbria. Fimbrial endometriosis may represent a distinct entity originating in situ rather than by implantation. It is also possible for endometriosis to occur in other portions of the tube, particularly near the ampulla. These menstruating foci may occur in differentiated tuba) mucosa or implanted endometrial tissue. Then, if the fimbria becomes sealed, a hematosalpinx due to functioning endometriosis may occur.

Finally, I would like to cite the case of a patient who had had a total hysterectomy and bilateral salpingo-oophorectomy for extensive endometriosis. Unfortunately, because of extensive cul-de-sac disease, the cervix was not removed. In order to prevent the development of vasomotor symptoms the patient was given sodium estrone sulfate at an initial dose of 1.25 mg. Apparently, this was inadequate and the dose was increased to 5.0 mg daily. When I saw the patient about two years later, she was referred because of a large, cauliflower growth of the cervix. Biopsies revealed active endometriosis. Behind the cervix the vagina was filled with blue nodules and there was fixation of the recto-sigmoid to the upper vagina. This process had been stimulated by the excessive estrogen dosage.

The exogenous estrogen was discontinued and the patient was given medroxyprogesterone acetate in a dose of 100 mg every two weeks for four doses and then 200 mg monthly. Three months later, marked regression had occurred and a cervicectomy was performed together with excision of the upper vagina and a segmental resection of the rectosigmoid.

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