Introduction
Adenomyosis has long been an underdiagnosed condition of the uterus (1). With the advent of uterine embolization of fibroids, interest in adenomyosis has increased. How often is it mistaken for fibroids? Can it be treated by embolization? Is it a cause for failure of embolization? With modern imaging techniques, adenomyosis can be diagnosed without surgery and thus we are able to begin to understand the natural history of the condition and to test the effectiveness of non-surgical therapies.

Pathology Adenomyosis is the presence of uterine lining tissue deep within the myometrium or muscular wall of the uterus (1) (see Figure 1). When diffuse, the uterus becomes enlarged, although rarely larger than a pregnancy of 12 weeks size. The adenomyosis tissue can extend throughout the lining of the uterus or in just one spot (focal). When focal, a localized collection of adenomyosis tissue may form a mass-like adenomyoma. Adenomyosis most commonly occurs in women who have had children, raising questions as to a possible role that pregnancy may have in its development (2). Uterine trauma during childbirth and post-partum infection have been suggested as possible causes of adenomyosis. No definitive cause has been identified and certainly adenomyosis can occur in women who have never been pregnant.

Figure 1: Surgical specimens after hysterectomy. On the left is a uterus with several large fibroids, some of which are indicated. On the lower right, the specimen has 3 small fibroids, but also extensive adenomyosis (arrows), which appears as a thickening of the inner portion of the muscle wall of the uterus, which is called the junctional zone.

The most common symptom of adenomyosis is abnormally heavy menstrual bleeding. Severe cramps are a frequent accompaniment when the adneomyosis exceeds 80% or more of the uterus (2). There is usually globular enlargement in the uterus on pelvic examination and the uterus may be somewhat boggy if the adenomyosis is advanced. The posterior wall of the uterus is more commonly involved than the anterior.

Adenomyosis and particularly adenomyomas are commonly misdiagnosed as fibroids, because the symptoms are similar. The uterus is often enlarged, and ultrasound imaging often fails to distinguish the two conditions. This can be a particular problem if myomectomy is undertaken. Adenomyosis has a poorly defined border and is not “shelled out” as leiomyomas may be. An attempted myomcetomy for “fibroids” on a patient with adenomyosis can result in extensive bleeding and may result in the need for hysterectomy.

Imaging
Modern imaging methods have been a great aid in accurately diagnosing adenomyosis (3). With modern ultrasonography, the diagnosis can frequently be made, although the changes can be subtle. The findings may include myometrial thickening with increased or decreased echogenicity of the myometrium, a poorly defined area of heterogeneous myometrium, or cysts. The sensitivity of transvaginal sonography ranges from 53-89% and specificity of 50 to 89%.

MR imaging increases both sensitivity (88-93%) and specificity (66-91%) of the diagnosis of adenomyosis. The signal intensity is similar to that of the junctional zone and usually is perceived as a thickened junctional zone to greater than 12 millimeters. Usually there is focal thickening of the junctional zone as well. On T2 weighted images, foci of increased signal are seen, representing islands of endometrium within the hypertrophied myometrium. Variable enhancement patterns are seen depending on the present of cystic areas. A common and useful finding is the relatively mild distortion of the endometrial cavity that occurs with even advanced adenomyosis (see Figure 2) It exerts much less mass effect than fibroids and this is a helpful finding differentiating when adenomyosis from fibroids.

Figure 2: MRI scan from the side showing a uterus with extensive adnomyosis (black arrows), which appears as a darker shade of gray on this scan when compared to the normal portions of the uterine wall (white arrows).

Current Therapies

The definitive therapy of adenomyosis is hysterectomy and commonly the diagnosis is not confirmed or even suspected until examination of the removed uterus. Surgical resection of the adenomyosis alone is not technically feasible in most cases. Until recently, even when the diagnosis has been suggested pre-operatively, hysterectomy was the only option to offer.

In recent years there have been investigations of various less invasive therapies for adenomyosis. In Europe, a levonorgestrel-releasing intrauterine device has been shown to be effective in controlling menorrhagia caused by adenomyosis (4). While the treatment is effective in the short term, the symptom control rapidly dissipates once the therapy is terminated. Endometrial ablation has been attempted, and with very superficial adenomyosis, endometrial ablation can be effective. However, if the penetration exceeds 2 millimeters, ablation usually fails to control bleeding (5).

UAE for Adenomyosis

It is not yet clear what embolotherapy may have to offer in controlling the symptoms from adenomyosis. There were three recent reports of experience with embolization in patients with adenomyosis. Two small studies demonstrated that in patients with fibroids and adenomyosis, embolization had similar rates of symptomatic improvement. In a small group (N=13) at Georgetown, 92% had symptomatic improvement in both menorrhagia and pelvic pain and pressure. In this series, there was reduction in the fibroid volume and uterine volume. There was not a significant change in the internal appearance of the adenomyosis, although in some cases there was regression of the adenomyosis extent (6). At Albany Medical School, Siskin treated 14 patients with focal adenomyomas or diffuse adenomyosis (7). In 90% of the patients, there was improvement in symptoms. Regression in uterine volume, focal adenomyoma volume, and thickness of the junctional zone was noted in all cases,

Ahn and his associates from Korea presented a much larger series (N=65) at the SCVIR 2000 (8). Twenty-nine percent of the group had both myomas and adenomyomas, with the balance having adenomyosis alone. Among all patients, 93.8% reported improvement in symptoms. The authors used varying sizes of polyvinyl alcohol particles, and commented that coagulation necrosis only occurred when particles of 355-500 micron size or smaller. They suggested that this finding is necessary to assure clinical improvement. The group at Georgetown used 500-710 micron size particles and did not see infarction of the adenomyosis, but had similar rates of symptomatic improvement.

Certainly additional study is needed to determine the role that UAE will play in the treatment of adenomyosis, but these initial reports are very encouraging. The optimal method for embolization has yet to be determined and validated outcome measures have yet to be used in assessing embolotherapy.

Summary

Adenomyosis is a difficult condition to both diagnose and manage, with hysterectomy the most commonly used definitive therapy. With the more extensive use of MRI as a gynecologic imaging tool, the diagnosis of adenomyosis will become more accurate and the testing of new therapies, including uterine embolization, will be greatly facilitated. With the initial positive reports of uterine embolization as a possible therapy, there is hope that alternatives to surgery may soon be available.

UAE for Adenomyosis at Georgetown University

Last year we began a protocol to determine whether patients with predominant adenomyosis (with few or no fibroids) could be successfully treated with uterine embolization. While the initial results are encouraging, the number of patients treated thus far has been small and the follow-up duration is relatively short. We are continuing to enroll patients in this study and would be happy to evaluate patients for inclusion. There are no research funds available to provide the treatment. The study uses validated measures of heavy bleeding and quality of life questionnaires to assess symptom status before and after treatment. MRI's are obtained at baseline and at 3 months after treatement.

For additional information, please call us at (202)784-5478 or email us at FIBROIDINFO@gunet.georgetown.edu.

References

1. Azziz R. Adenomyosis: Current perspectives. Obstet Gynec Clin of NA 1989;16:221-235.
2. Siegler A, Camilien L. Adenomyosis. Jour. of Reprod. Medicine 1994;39:841-853.
3. Outwater E, Siegelman E, Van Deerlin V. Adenomyosis: Current concepts and imaging considerations. AJR 1998;170:437-441.
4. Fedele L, Bianchi S, Raffaelli R, Portuese A, Dorta M. Treatment of adenomyosis-associated menorrhagia with a levonorgestrel-releasing intrauterine device. Fertility and Sterility 1997;68:426-429.
5. McCausland A, McCausland V. Depth of endometrial penetration in adenomyosis helps determine outcome of rollerball ablation. Am J Obstet Gynecol 1996;174:1786-1794.
6. Thomas J, Gomez-Jorge J, Chang T, Jha R, Walsh S, Spies J. Uterine fibroid embolization in patients with leiomyomata and concomitant adenomyosis: experience in 13 patients. JVIR 2000;11:191.
7. Siskin G, Tublin M, Stainken B, Dowling K, Ahn J, Dolen E. Bilateral uterine artery embolization for the treatment of menorrhagia due to adenomyosis. JVIR 2000;11:191.
8. Ahn C, Lee W, Sunwoo T, Kho Y. Uterine arterial embollization for the treatment of symptomatic adenomyosis of the uterus. JVIR 2000;11:192.