Transvaginal ultrasonography in the differential diagnosis of

adenomyoma versus leiomyoma

Luigi Fedele, MD: Stefano Bianchi, MD: Milena Dorta, MD: Fabrizio Zanotti, MD: Diana Brioschi, MD: and Silvestro Carinelli, MDb

Milan, Italy

OBJECTIVE: We evaluated the reliability of transvaginal ultrasonography in the differential diagnosis of

adenomyoma versus leiomyoma. STUDY DESIGN: Preoperative transvaginal ultrasonographic results were compared with postoperative

pathologic findings in 405 women who underwent surgery for symptomatic uterine nodularity.

RESULTS: For adenomyoma diagnosis, transvaginal ultrasonography demonstrated a sensitivity of 87%, a specificity of 98%, a positive predictive value of 74.1 %, and a negative predictive value of 98.6%, compared with a sensitivity of 96.1 %, a specificity of 83.3%, a positive predictive value of 98.4%, and

negative predictive value of 35.7% for leiomyoma diagnosis.

CONCLUSION: Transvaginal ultrasonography is an effective, noninvasive, and relatively inexpensive procedure for the preoperative differential diagnosis of adenomyoma versus leiomyoma. (AM J OSSTET

GVNECOL 1992;167:603-6.)

Key words: Transvaginal ultrasonography, adenomyoma, leiomyoma, diagnosis

Adenomyosis may present in two distinct forms, dif­fuse and nodular. In the diffuse form the foci of ad­enomyosis are distributed diffusely in the myometrium, and in the nodular form they consist of circumscribed nodular aggregates termed adenomyomas. At clinical ex­amination adenomyomas are generally mistaken for uterine leiomyomas. Until now preoperative differen­tial diagnosis between the two tumors has been almost impossible, and definitive diagnosis has had to wait for pathologic findings.

The recent availability of the transvaginal ultra so no­graphic probe has provided the gynecologist with a new and sophisticated method of investigating uterine mor­phologic features. In the current study we evaluated the reliability of transvaginal ultrasonography in the diagnosis of adenomyoma in a group of patients un­dergoing surgery for symptomatic uterine nodularities by comparing the ultrasonographic findings with the postoperative pathologic results.

Material and methods

All 452 women with symptomatic (menorrhagia, in­fertility, pelvic pain) uterine nodularities admitted to our department to undergo myomectomy or hyster­ectomy from October 1988 to October 1990 were en-

From the 2nd Department of Obstetrics and Gynecology, University of Milan,' and the Department of Pathology, Istituti Clinici di Per­fezionamento. b

Received for publication September 5, 1991; revised March 16, 1992; accepted March 31, 1992. Reprint requests: Luigi Fedele, MD, /slituto Ostetrico-Ginecologico II, Universita' di Milano, via Commenda, 12, 20122-Milano, Italy. 611 138303

rolled in the study. Myomectomy was performed in 147 and hysterectomy on 305. The choice of surgical treat­ment was based on age and desire for childbearing. The median age was 43 years (range 21 to 54 years).

All the women were scheduled to undergo transva­ginal ultrasonography the day before surgery with An­saldo AU 440 or Ansaldo AU 560 equipment and a transvaginal probe of 6.5 MHz. The sonographer di­agnosed adenomyoma in the presence of a dis homo­geneous circumscribed area in the myometrium, with indistinct margins and containing anechoic lacunae of varying diameter; leiomyoma was diagnosed when a nodular formation with well-defined margins, hetero­geneous structure, and variable echogenicity was de­tected in the myometrium.

Postoperatively, the surgical specimen was examined by the pathologist who, in addition to performing rou­tine tests, analyzed all the uterine nodularities. Adeno­myoma was diagnosed when a circumscribed nodular aggregate of smooth muscle and endometrial glands was seen together with compensatory hypertrophy of the myometrium surrounding the site of ectopic en­dometrium. The presence of endometrial stroma was not required for the diagnosis. I

The pathologic findings were compared with those obtained by transvaginal ultrasonography. Nodular formations of < 1 cm in diameter were not considered because they are frequently fulgurated in conservative interventions.

The sensitivity and specificity of transvaginal ultra­sonography and the predictive values of normal and abnormal tests were calculated according to Stempel.2

603

604 Fedele et al. September 1992 Am J Obstet Gynecol

Fig. 1. Adenomyoma of posterior wall of uterus. Transvaginal ultrasonography (A) and schematic drawing (8) show aggregate of anechoic lacunae with indistinct margins. C, Gross anatomy; D, microscopic findings of the same case. (D, Original magnification x 10.)

Results

Transvaginal ultrasonography was not performed in four women who were virgins or in 43 other patients for personal reasons. It was found acceptable by the remaining 405 women; exploration of the uterus was satisfactory in 381 whereas marked uterine enlarge­ment prevented complete exploration of the fundus in 24.

The sonographer identified a total of 920 nodular­ities and diagnosed 27 adenomyomas in 26 patients (one patient had two adenomyomas) (Figs. I, A and B,

and 2, A and B) and 893 leiomyomas in 359 cases (four patients had both leiomyoma and adenomyoma). The pathologist found 949 nodularities, 29 more than the sonographer reported. These 29 nodularities were all myomas of <2 em in diameter, mainly located in the fundus. Pathologic examination revealed the presence of 23 adenomyomas (2.4%) in 22 patients (5.7%) (Figs. I, C and D , and 2, C and D). Three of these nodularities had been diagnosed as leiomyomas at ultrasonography whereas in the other 20 pathologic examination con-

firmed the uitrasonographic finding. The other seven nodularities diagnosed as adenomyomas by ultraso­nography were found to be leiomyomas with degen­erative aspects at pathologic examination. In all these cases pathologic study revealed multiple areas of cystic degeneration that at ultrasonography appeared as ane­choic areas. Reviewing the sonograms after pathologic diagnosis, we observed that in five of these cases the margins of lesions were clearly distinct, but this finding was not correctly considered . One nodularity, diag­nosed as leiomyoma by ultrasonography and initially by pathologic examination, was a leiomyosarcoma. All the remainsing 918 nodes identified by the pathologist were leiomyomas.

With adenomyoma assumed to be an abnormal con­dition and the other types of node considered "nor­mal ," transvaginal ultrasonography demonstrated a sensitivity of 87% and a specificity of 99%, the predic­tive value of an abnormal ultrasonographic scan was 74.1% and that of a normal one of 99.6%. When we considered leiomyoma as an abnormal condition and

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Ultrasonography for diagnosis of leiomyoma vs adenomyoma 605

Fig. 2. Adenomyomas of posterior wall of uterus. Transv<lginaluitrasolJography (A) and schemati( drawing (B) show two large anechoic areas sUlToundcd by disholllogencous myometrium. C, Gross anatomy; D, microscopic findings of the same case. (D, Original lllagnification x ) 0.)

the other Lypes of nodularity as "normal," we found that the sensitivity of transvaginal ultrasono~raphy was 96.1 ric and the specificity was 83.3'}f,; an abnormal scan had a predictive value of 98.47< and for a normal one the value was 35.7%.

Comment

III our study transvaginal ultrasonography was a valid diagnostic tool for the preoperative differentia­tion of adenomyoma from leiomyoma. The study was prospective and the series was large.

The prevalence of adenomyosis reported in the lit­erature v<Hies from 5'i';' to 70%.' In the current study, which considered only the nodular type, the prevalence was 2.4% with respect to the total number of uterine nodularities and 5.7% with respect to the patients who underwent operation.

Adenomyomas may be isolated or multiple and they

develop in the myometrium. They are often confused with intramural myomas. Even on the operating table, in spite of their darker color and lesser consistency. Sometimes they present as polypoid masses in the en­dometrial cavity, and the possibility of malignant trans­formation is recognized.'

During surgical removal it is evident that adeno­myomas, unlike leiomyomas. do not have planes of cleavage with I-espect to the myometrium. Leiomyomas usually compress the surrounding myometrium. thus creating a pseudocapsule from which the tumor can easily be enucleated at surgery. whereas adenomyomas interdigitate with normal smooth muscle, making their surgical removal difficult or impossible. Therefore hys­terectomy remains the main therapeutic option for ad­enomyoma,' and it is of fundamental importance for the surgeon to know the nature of the uterine nodu­larities to be able to program a conservative operation.

606 Fedele et al.

Numerous attempts have been made to find a reliable instrument to diagnose adenomyosis. Unfortunately, the studies performed did not considered adenomy­omas and the more common diffuse form of the disease separately. Hysterosalpingography sometimes demon­strates multiple spiculations or tuft defects leading from the uterine cavity to the myometrial wall. Such images of adenomyosis are not readily distinguishable from those produced by vascular or lymphatic extrav­asation.' Hysterosalpingography is thus no longer used for the diagnosis of adenomyosis. The diagnostic ca­pability of abdominal ultrasonography has been eval­uated in various studies. In the investigation of Walsh et al.6 of four patients with histologically verified ade­nomyosis, abdominal ultrasonography revealed char­acteristic irregular cystic spaces of 5 to 7 mm disrupting the normal fine speckled echo pattern of the uterus (honeycomb image). Buli et aJ.7 did not detect adeno­myosis by ultrasonography. Bohlman et al.B reviewed the sonograms of seven women with pathologically ver­ified extensive adenomyosis and observed uterine ab­normal images at ultrasonography in six cases: en­larged uterus, increased thickness of the posterior wall, and a slight increase in uterine echogenicity. Also mag­netic resonance imaging has been used in the diagnosis of adenomyosis. Mark et al. 9 assessed the diagnostic capability of this method in 21 premenopausal patients with a strong clinical indication of adenomyosis. All eight cases affected by the diseases were correctly di­agnosed by magnetic resonance imaging. Focal ade­nomyosis appeared as a low-signal-intensity mass poorly marginated from the adjacent myometrium. To­gashi et al. IO studied the potential of magnetic reso­nance imaging in the differentiation of adenomyosis from leiomyoma in 93 patients with enlarged uteri. In 92 cases magnetic resonance imaging correlated well with pathologic findings but in one woman did not distinguish nodular adenomyosis from degenerate leio­myoma.

The current findings confirm the limitations of trans­vaginal ultrasonography in the investigation of disease in an enlarged uterus observed by us in a previous study" because of the impossibility of adequately ex­ploring the fundus of a markedly enlarged uterus.

September 1992 Am J Obstet Gynecol

Although the sensitivIty and specificity of transva­ginal ultrasonography were elevated, the predictive value of an abnormal test was 74.1 %. This means that in one case out of four a diagnosis of adenomyoma is made in the presence of a leiomyoma. Therefore, if the intraoperative finding does not correspond to the ultrasonographic diagnosis, we would recommend per­forming immediate histologic examination.

In conclusion, the sensitivity of preoperative trans­vaginal ultrasonography in identifying adenomyoma is good. Its reliability may be somewhat less than that of magnetic resonance imaging, but it is a rapid, nonin­vasive, and relatively inexpensive diagnostic method that could be an important tool for the study of this neglected disease.

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