tumors in the lower pelvis as imaged by vaginal sonography

GYNECOLCMXC ONCOLOGY 37, 224-229 (1990)

Tumors in the Lower Pelvis as Imaged by Vaginal Sonography SETH GRANBERG, ANDERS NORSTRGM, AND MATTS WIKLAND

Department of Obstetrics and Gynecology, University of Giiteborg, Giiteborg, Sweden

Received June 16, 1989

Ultrasound is a sensitive tool for the diagnosis of cystic tumors in the lower pelvis of women. Most knowledge about the ultrasound image of such tumors is based on abdominal scanning. The value of vaginal sonography for evaluation of such tumors has, to the best of our knowledge, so far not been studied. This study was ahned at relating the vaginal sonographic image of tumors in the lower pelvis with the results of macro- and microscopic examination of the tumor. Special interest was paid to establishing ultrasound criteria for classifying unilocular tumors as benign or malignant. One hundred and eighty women who were operated on for pelvic tumors were inluded in the study. All women were evaluated by vaginal sonography the day before surgery. Ninety-four women were postmenopausal and eighty-six were still menstruating. Vaginal ultrasound charactized the tumor correctly as related to macroscopic examination in 96% (172/180). The sensitivity of vaginal sonography in identifying benign and malignant tumors was 82%, and the specificity, 92%. None of the unilocular tumors was malignant. Papillary formations on the inside of the cyst wall indicated an increased chance of the tumor’s being malignant. There was a clear correlation between size of tumor and malignancy except for unilocular tumors. Va- ginal sonography was shown to be accurate in characterizing cystic tumors in the lower pelvis. The present results also indicate that the probability that unilocular tumors less than 10 cm in diameter and without papillary formations, are malignant is low, irrespective of the woman’s age. o 1990 Academic press, IX.

INTRODUCTION

Ultrasound has proved to be a sensitive diagnostic instrument for identifying ovarian tumors or other pathology in the lower pelvis of women, even when compared with computerized tomography (CT) [ 1,2]. Almost all knowledge about the ultrasound image of ovarian tumors is based on abdominal ultrasound scanning [3-71. The experience of vaginal sonography with regard to ovarian normality and pathology is limited. So far, most studies deal with the use of vaginal sonography for measuring follicles or follicle aspiration in human in vitro

fertilization programs [8,9]. Transducers used for vaginal sonography are often of high frequency, the better resolution as compared to abdominal transducers enabling a more detailed imaging of ovarian tumors. However, there is a need for studies where vaginal sonography is evaluated with regard to what can be seen on the image produced of tumors in the lower pelvis. The image then has to be compared with the results of macro- and microscopic examination [lo, 111. On the basis of such studies it will be possible to assess the advantages and dis- advantages of using vaginal sonography to study pathological conditions in the lower pelvis of women.

Unilocular tumors are known to be rather common in postmenopausal women [ 12- 161. The question often arises as to whether such cystic tumors should be removed or not. What criteria should be used? The woman’s age, the size of the tumor, the complexity of the tumor as imaged by ultrasound? Is it really necessary to operate on all women in whom a unilocular tumor is found in the lower pelvis? The better resolution of vaginal sonography, the more frequent use of this instrument, and the increased skill and experience among gynecologists will increase the number of cysts found in women. This means that it is important to establish some ultrasound criteria to support a decision to operate or not when a unilocular tumor has been diagnosed by vaginal sonography.

The aim of this study was to compare the findings of vaginal sonography with those of macro- and microscopic examination in women with a previously diagnosed pelvic mass and in whom surgery was planned irrespective of what was found at the vaginal scan, mak- ing it possible to compare the ultrasound diagnosis with reality.

MATERIALS AND METHODS

During the period 1987 through 1988, women sched- uled for elective surgery due to adnexal masses were

224 0090-8258/!30 $1.50 Copyright 0 1990 by Academic Press, Inc. AU rights of reproduction in any form reserved.

VAGINAL SONOGRAPHY OF TUMORS IN LOWER PELVIS

No. of women

50

1 •l Total

40

30

20

10

0 I

Benign

q Malign

<20 20:29 30139 40-49 50159 SO:69 >70 10 year age cohorts

FIG. 1. Histogram of the age distribution for women with benign and malignant tumors.

scanned endovaginally prior to laparotomy. The group the widest diameter of the tumor was measured in two included 180 women with the age distribution shown in planes. At the ultrasound examination the tumor was Fig. 1. The reason for surgery was to exclude malignancy classified as being of ovarian or uterine origin. Further- of the palpated tumors. Ninety-four women were post- more, the tumor was, both by ultrasound and at the menopausal and 86 were menstruating. None of the macroscopic examination by the pathologist, classified women had previously been operated on due to ovarian as unilocular, unilocular solid (20-80% of the tumor was tumors or any other abdominal tumors. All tumors had solid), multilocular, multilocular solid (20-80% of the been found at a gynecological examination performed 1 tumor was solid), or solid. Presence or absence of pap- week to 1 month prior to surgery. Seventy-one percent illary formations on the inside of the cyst wall was reg- of the women had gynecological symptoms that made istered both at the macroscopic examination and by ul- them contact their doctors. The rest of the tumors were trasound. Papillary formations were defined by ultra- diagnosed at a routine gynecological checkup. All women sound as areas of high echogenicity, protruding from the were examined by a trained gynecologist the day before inside of the cyst wall or from internal septa of the cyst. planned surgery, when earlier findings were verified. One The occurrence of papillary formations was graded as hundred twenty-three women underwent dilatation and follows: 0 = no papillary formation observed by ultra- curettage (D&C) as well as bimanual examination under sound or at macroscopic examination of the inside of the general anaesthesia prior to laparotomy. cyst wall (Fig. 2), 1 = one to five papillary formations

All women were examined by vaginal sonography the day before surgery. All these examinations were performed by the same doctor. A vaginal transducer (Brtiel & Kjaer, Naerum, Denmark) was used. The transducer has a mechanical sector of 112” and a frequency of 7 MHz. The focal range of the transducer is 6 cm from the transducer tip. Prior to the examination, the patient voided her urinary bladder. In patients in whom the tumor occupied more or less the whole lower pelvis and vaginal scanning could not image the whole tumor, abdominal scanning was also performed to obtain a sonographic image of the tumor. For the abdominal scan a sector transducer with a frequency of 3.5 MHz (Diasonic DRF 1001 Milipitas, CA) was used. At vaginal scanning,

FlG. 2. UniIocuIar cyst as imaged by vaginal sonography. Orien- tation: longitudinal scan with bottom of figure representing vaginal fomix. No papillary formation is found (grade 0).

225

226 GRANBERG, NORSTROM, AND WIKLAND

FIG. 3. Cystic tumor as imaged by vaginal scanning. White arrow shows papillary formation grade 1. Orientation is the same as for Fig. 2.

(Fig. 3), grade 2 = more than five papillary formations (Fig. 4). According to the ultrasound image, a tumor was considered to have a high probability of being malignant the more complex it looked on ultrasound.

The ultrasound image as classified above was compared with the results of macroscopic and microscopic examination of the tumor after surgery; this examination was performed by the pathologist (Table 1).

RESULTS

Of 180 women examined, 39 (21.5%) were found to have a malignant tumor (Fig. 1, Table 2). From the age of 50, there is a dramatic increase in malignant tumors.

Palpation revealed the tumor as ovarian origin in 137 women; in 43 women the origin of the tumor could not be determined. Twelve turned out to be of unterine origin and 31 of ovarian origin. The corresponding figures for vaginal ultrasound were 156 and 11; all of these turned out to be of ovarian origin.

Vaginal ultrasound characterized 13 solid tumors as

FIG. 4. Multilocular tumor as imaged by vaginal scanning. White arrows show papillary formation grade 2 (see Materials and Methods). Orientation is the same as for Fig. 2.

being of uterine origin. At the macroscopic examination they were all described as interstitial myomas 5 to 8 cm in diameter. Five tumors were not diagnosed as uterine by sonography. One of these was a malignant uterine sarcoma. Four other tumors were subserous uterine myomas measuring between 8 and 14 cm in diameter, and vaginal sonography described these solid tumors as ovarian masses. Fourteen of the solid tumors were of ovarian origin and in all cases correctly diagnosed by ultrasound. The macroscopic examination at surgery revealed 162 as ovarian and 18 as uterine.

Of 45 unilocular tumors, 44 were classified as unilocular by ultrasound. However, another one was classified as solid by vaginal ultrasound but turned out to be a unilocular cyst. One of the tumors, larger than 10 cm in diameter, was classified as unilocular by ultrasound but turned out to be multilocular at macroscopic examination. The comparison of the macroscopic appearance of the tumors with the ultrasound image is shown in Table 1. There were no malignant tumors among those classified as unilocular (Table 3).

Thirteen of forty-five (29%) unilocular cysts were found in women over the age of 50, and 15 of 45 (33%) in women between 40 and 50 years of age.

Grade 1 papillary formations according to macroscopic characterization were found in 9% of the tumors that were benign according to the histopathological diagnosis. The corresponding figure for ultrasound was 12%. Of those tumors with grade 2 papillary formations 4%

TABLE 1 Correlation of Ultrasound Image and Macroscopic Characterization of Tumors in the Lower Pelvis

Macroscopic characterization

Ultrasound image Unilocular Unilocular solid Multilocular Multilocular solid Solid Total

Unilocular 44 0 1 0 0 45 Unilocular solid 0 11 1 0 0 12 Multilocular 0 0 43 0 0 43 Multilocular solid 0 1 2 42 0 45 Solid 1 0 0 2 32 35

Total 45 12 47 44 32 180

VAGINAL SONGGRAPHY OF TUMORS IN LOWER PELVIS 227

TABLE 2 Size of Tumor as Measured by Ultrasound and the

Relationship to Malignancy

Size (cm)

<5 5-10 >lO Total

Benign 53 77 11 141 Malign 1 10 28 39

Total 54 87 39 180

TABLE 3 Number of Benign or Malignant Pelvic Tumors as Diagnosed

by Ultrasound and the Related Histological Diagnosis

Macroscopic characterization of tumor

Ultrasound diagnosis

Benign Malignant

Histopathological diagnosis

Benign Malignant

ullilocu1ar 45 0 45 0 Unilocular solid 12 0 11 1 MuItiIocular 34 9 39 8 Multilocular solid 15 30 18 26 Solid 31 4 28 4

Total 137 43 141 39

TABLE 4 Papillary Formation in Ovarian Cystic Tumors as Diagnosed

by Ultrasound and by Macroscopic Examination

Ultrasound Macroscopic Grading of papillary formation Benign Malignant Benign Malignant

Grade 0 92 2 99 3 Grade 1 12 2 IO 2 Grade 2 0 37 4 27

Total 104 41 113 32

TABLE 6 Accuracy of Vaginal Ultrasound in Differentiation between

Benign and Malignant Pelvic Tumors

Histology

Ultrasound Benign

Benign 130 Malignant 11

Total 141

Malignant Total

7 137 32 43 39 180

(4/l 13) were benign while 84% (27/32) were malignant (Table 4). In three of the unilocular tumors small papillary formations were found (Grade 1). None of these tumors was malignant.

Eleven out of one hundred forty-one (8%) benign tumors were larger than 10 cm in diameter, as compared with 28 of 39 (72%) malignant tumors (Table 2). Size of tumors was further analyzed with respect to macroscopic characterization (Table 5). As can be seen from Table 5, all of the unilocular tumors larger than 10 cm in diameter were benign. Of the malignant tumors, one was less than 5 cm.

The more complex the macroscopic appearance and the ultrasound image of the tumors, the higher the pro- portion that were malignant. As can be seen from Table 3, 5% (26/44) of the multilocular solid tumors were malignant.

By ultrasound, 137 tumors were classified as benign. Among these, 7 turned out to be malignant. Forty-three tumors were judged to be malignant by ultrasound; however, histopathological evaluation revealed 11 benign tumors among these 43 (Table 6). The specificity of vaginal ultrasound with regard to malignancy is 92%, and the sensitivity, 82%.

DI!X!USSION

Vaginal ultrasound is being used more frequently by gynaecologists for the diagnosis of gynecological dis-

TABLE 5 Size of Tumor as Measured by Ultrasound and the Relationship to Macroscopic Characterization and Histology

Macroscopic characterization 15 cm

Benign

5-10 cm >lO cm <5 cm

Malignant

5-10 cm >lO cm Total

Unilocular 19 19 7 0 0 0 45 Unilocular solid 6 4 1 0 0 1 12 Multilocular 10 27 2 1 2 5 47 Multilocular solid 2 16 0 0 7 19 44 Solid 16 11 1 0 1 3 32

Total 53 77 11 1 10 28 180

Histopathological diagnosis

228 GRANBERG, NORSTROM. AND WIKLAND

eases. The reason is that it is easy to use in connection with a gynecological examination, it is easily handled, and the image is rather easily interpreted after some training. This means that more tumors are disclosed than would have been the case if only gynecological examination had been performed [12-161. Consequently, the following question more frequently arises: How should this knowledge of the existence of a pelvic tumor be handled? Are the same routines valid for tumors detected by ultrasound as for those detected by palpation? Does ultrasound aid any hitherto concealed information to al- low the avoidance of surgery in some women? Is the handling dependent on the age of the women? It has always been a rule that if a tumor is palpated in a postmenopausal woman it should be removed surgically [18- 201. Does this also apply to tumors found by vaginal ultrasound examination? To answer these questions it is important to determine if there are any ultrasound criteria that could be used to characterize the tumor as benign and thus avoid major surgery.

As previously shown by our group, a unilocular cyst, judged according to its macroscopic appearance, seems to carry a very low risk of malignancy [2 11. In the present study, it was found that vaginal sonography diagnosed unilocular cysts correctly in 98% (44/45). None of the tumors that were classified as unilocular cysts by vaginal sonography was malignant (see Table 3). Earlier studies of ultrasound diagnosis of simple cystic tumors in postmenopausal women have revealed that the probability of these tumors’ being malignant is probably very small [12-141. However, these studies included not only simple cysts but also multicystic tumors [12,14], which are known to have an increased chance of being malignant.

As can be seen from Table 6, the sensitivity and the specificity of vaginal ultrasound in differentiating between benign and malignant tumors is comparable to what has been found for abdominal scanning [22].

It has always been claimed that the size of an ovarian tumor correlates with malignancy [12,23]. Such a correlation was noted in this study as well, if the tumors were grouped according to size and malignancy (Table 2). It is, however, interesting to note that such a correlation was not found in this study for unilocular tumors, in agreement with earlier results from our group [21]. Such a classification with correlation to size, as performed in Table 5, has to the best of our knowledge not been performed before.

One must be aware of the difficulties involved in classifying a tumor as unilocular if it is larger than 10 cm. In such large tumors, abdominal and vaginal scanning should be combined to enable determination of the exact texture of the tumor.

It has been claimed that areas protruding from the cyst

wall into the cyst represent malignant tissue [24]. If so, this would mean that cystic (uni- or multilocular) tumors with such areas identified by ultrasound would carry a higher probability of malignancy. It thus seemed important to try to grade the “papillary formations” as diagnosed by ultrasound and relate grade to malignancy. Since it is very difficult to measure these areas in a standard manner, the grouping was performed arbitrarily according to the criteria presented under Materials and Methods. It was found that the higher the grade, i.e., the more such areas that could be imaged by ultrasound, the higher the probability of malignancy (Table 4). Note, however, that two tumors were classified as malignant at histopathology despite the fact that ultrasound did not reveal any papillary formations. These tumors were multilocular solid but no papillary formations could be seen in the cystic parts of the tumors. On the other hand, not all tumors that contained papillary formations were malignant. The advantage of using vaginal sonography to image papillary formations is that these transducers are usually of high frequency, which might increase the chances of identifying these areas. Solid tumors can sometimes be difficult to identify, by vaginal ultrasound, since their echo pattern sometimes is very much the same as that often produced by bowel contents. Furthermore, where a solid tumor is observed isolated from the uterus and the ovaries, it can be difficult to state the origin and the nature of the tumor. In such a situation abdominal scanning can be of great help. Solid tumors are sometimes hypoechogenic, which means that they can be mis- taken for cystic tumors (see Table 1). If such uncertainty arises, the gain of the ultrasound is increased, which usually makes it possible to tell whether it is a solid or cystic tumor. Further, if an echo shadow appears behind the tumor it is often a solid tumor.

Interstitial myomas were easily diagnosed by vaginal sonography since these tumors often have a very typical hypoechogenic image which demarcates them from the myometrium. On the other hand, 14 solid tumors were described to be of adnexal origin due to the fact that no connection was found between the tumor and the uterus; it was assumed that the tumor did not engaged uterus.

It is very difficult or even impossible to use ultrasound to differentiate between benign and malignant tumor when dealing with a complex tumor. Thus, if the tumor as imaged by ultrasound is very complex, there is a high probability that it is malignant [23]. When this criterion was applied in this study to evaluate the tumor malignancy by means of vaginal sonography, there was a tendency to overdiagnose malignant tumors (Table 3). Of course, such a tendency could be expected if treatment of the patient were based on the ultrasound diagnosis. This was not the situation in this study, however, since

VAGINAL SONOGRAPHY OF TUMORS IN LOWER PELVIS 229

all the women were to be operated on. The reason for not classifying all complex tumors as malignant was that the medical history was known by the doctor performing the scan. This knowledge was included in the decision to classify the tumor as malignant or benign. In fact, this is often the case when dealing with ultrasound diagnosis; i.e., the ultrasound image must be considered in relation to the medical history of the patient.

It thus seems difficult, even by vaginal ultrasound with its excellent imaging, to exclude a tumor in the lower pelvis as malignant, except for unilocular cystic tumors. However, it seems that if it is not possible by vaginal sonography to reveal any papillary formations, echogenic areas, and/or internal septation in a cystic tumor less than 10 cm in diameter, probability that the tumor is malignant is probably low. Earlier results from our group [21] as well as the results from this study support the view that this is true irrespective of the woman’s age. Since unilocular cysts as diagnosed by ultrasound seem to carry a very low probability of malignancy, ultrasound-guided puncture can be an alternative to surgical removal of the cyst in young women, in whom major surgery could risk future fertility [25]. This action is necessary only if the cyst persists and causes some kind of discomfort to the woman.

In cases in which any other type of low pelvic tumor is diagnosed by ultrasound, laparotomy must be performed.

ACKNOWLEDGMENTS

This study was supported by grants from Btiiel & Kjaer, Naerum, Denmark; The King Gustav Jubilee Clinic Cancer Research Founda- tion, Gothenburg; and Goteborgs L&a&llskap.

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REFERENCES 20.

Coulam. C. M., Julian, C. G., and Fleischer, A. C. Clinical effi- 21. cacy of CT and US in evaluating gynecologic turnours, Appl. Ra- dio/. 11, 79-88 (1982). Fleischer, A. C., Walsh, J. C., Jones, H. W.. Shaff, M. I., and James, A. E. Sonographic evaluation of pelvic masses. Method of 22. examination and role of sonography relative to other imaging mo- dalities, Radiol. Clin. North Amer. 20. 397-412 (1982). Kratochwill, A., Urban, G., and Friedrich, F. Ultraschalldiagnos- 23. tik von adnextumoren, Wien. Min. Wochenschr. 15, 569-575 (1978). Von Zanke, S., Meinhold, P., and Eichhom, K.-H. Preoperative differentialdiagnose von gynecologischen tumor-en durch ultra- 24. schall, Zentralbl. Gynaecol. 53, 990-999 (1985). Schillinger, H. Sonographie zur fryherkennung und zur entschei- 25. dung der dignitaet. Oncologic 5, 264-270 (1985).

Smith, E. M., and Anderson, B. The effects of symptoms and

delay in seeking diagnosis stage of disease at diagnosis among women with cancers of the ovary, Cancer 56, 2727-2732 (1985).

Cambell, S., Goswamy, R. K., Goessens, L., and Whitehead, M. I. Real-time ultrasonography for determination of ovarian mor- phology and volume. A possible early screening test for ovarian cancer, Lancer 1, 425-426 (1982). Nilsson, L., Wikland, M., and Hamberger, L. Simplification of the method of in-vitro fertilization: Sonographic measurement of fol- Iicular diameter as the sole index of follicular maturity, 1. In Vitro

Fertil. Embryo Transfer 2, 17-20 (1985). Wiiand, M., Enk, L., Hammarbe rg. K.. and Nilsson, L. Use of vaginal transducer for oocyte retrieval in an IVF/ET program, J. Clin. Ultrasound 15, 245-251 (1987). AndoIf, E., and Jorgensen, C. A prospctive comparison of trans- abdominal and transvaginal ultrasound with surgical findings in gynaecological disease, J. Ultrasound Med., in press. Leibman, J. A., Kruse, B., and McSweeney, M. B. TransvaginaI sonography: Comparison with transabdominaI sonography in the diagnosis of pelvic masses, Amer. 1. Roentgenol. 151,89-92 (1988). AndoIf, E., SvaIenius, E., and Astedt, B. Ultrasonography for early detection of ovarian carcinoma, Brit. 1. Obstet. Gynecol. 93,

1286-1289 (1986). Goldstein, S. R., Subramanyam, 9.. Snyder, J. R., Belier, II., Raghavendra, B. N.. and Beckman, E. M. The postmenopausal cystic adnexal mass: The potential rde of ultrasound in conserv- ative management, Obstet. Gynecol. 73, 8-10 (1989). Rulin. M. C., and Preston, A. L. Adnexal masses in postmenopausal women. Obstet. Gynecol., 70, 578-581 (1987). Hall, D. A., and McCarthy, K. A. The significance of the postmenopausal simple adnexaI cyst, J. Ultrasound Med. 5, 503-505

(1986).

Goswamy. R. K., Campbell, S., and Whitehead, M. 1. Screening for ovarian cancer, Clin. Obstet. Gynecol. 10, 621-643 (1983). Barber, H. R., and Graber. E. A. The PMPO syndrome, Obstet.

Gynecol. 38, 921-923 (1971). Kase, N. G., and Weingold, A. B. Principles ofpractice of clinical

gynecology, Wiley, New York, p. 579 (1983). Danforth, D. N., and Scott, J. R. Obstetrics and gynecology, Lip pincott, Philadelphia, 5th cd., p. 1111 (1986). Jones, H. W., and Jones, G. S. Novaks textbook of gynecology,

Wiliams & Wilkins, Baltimore, 10th ed., p. 513 (1981). Granberg, S., Wikland, M., and Jansson, 1. Macroscopic char- acterisation of ovarian tumours and the relation to the histological diagnosis: Criteria to be used for ultrasound evaluation, Gynecol.

Oncol. 35, 139-144 (1989). Andolf, E., and Jorgensen, C. A prospective comparison of clinical ultrasound and operative exam of the female pelvis, 1. Ultrasound

Med. 7, 617-620 (1988). Levi, S., Awoust. J., and Carton, A. Ovarian tumours: Possible

ultrasonic distinction between benign and malignant? Ultrasound

and cancer, Excerpta Medica, Amsterdam, Vol. 587, pp. 165-176 (1982). Andersson, W. A., and Scotti, T. M. Synopsis of pathology,

Mosby. St. Louis, MO, 8th ed., pp. 838-839 (1972). Granberg, S., Crona, N., Enk, L., Hammarberg, K., and Wikland, M. Ultrasound guided puncture of cystic tumours in the lower pelvis of young women, 1. Clin. Ultrasound 17, 107-111 (1989).

tumors in the lower pelvis as imaged by vaginal sonography

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