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Imaging Stephen

of Uterine

Karasick,1

Anna

Leiomyomas

S. Lev-Toaff,1

and Michael

E. Toaff2

Advances in the medical and surgical treatment of uterine lelomyomas have stimulated interest in the imaging of these common tumors. The purpose of this essay is to illustrate the appearance of lelomyomas on images obtained with various techniques. The advantages of each technique in particular din-

ical circumstances

Fig. 1.-Plain homogeneous,

are discussed.

radiograph of pelvis shows large, circumferentially calcified myoma.

Uterine leiomyomas (also called myomas and fibroids) are the most common solid uterine neoplasm, occurring in 2040% of all women during their reproductive years [1]. They are well-circumscribed benign lesions composed primarily of smooth

muscle

with

Fig. 2.-Segfttal sonogram shows hypoechoic mass (arrow) that could be either a fibrold or an adnexal mass. A CT scan of the same patient showed a lobulated uterus but did delineate a discrete mass. MR imaging (not shown) revealed a mural/subserous fibroid.

various

amounts

AJR 158:799-805,

AprIl

1992 0361-803X/92/1584-0799

C American

Roentgen

Ray Society

connective

Fig. 3.-Transvaglnal s.gfttal sonogram shows two small hypoechoic masses (straight arrows) distorting endometrial echo that were thought to represent either polyps or subrnucous fibrolds. Curved arrows indicate interrupted endometrial echo. at surgery.

Submucous

Received October 8, 1991 ; accepted after revision November 25, 1991. I Department of Radiology, Thomas Jefferson University Hospital, 11 1 S. 1 lth St., Philadelphia, PA 19107. Address reprint requests Department of Obstetrics and Gynecology, Hahnemann University Hospital, Broad and Vine Sts., Philadelphia, PA 19102.

2

of fibrous

fibroids

to S. Karasick.

were

found

800

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tissue.

A pseudocapsule

of areolar

tissue

KARASICK

ET AL.

one or

ing to the location.

containing

AJR:158,

From

an imaging

two feeding vessels surrounds the tumor. As fibroids enlarge, they may outgrow their blood supply, resulting in ischemia

also important

and degeneration

Also, a submucous fundal myoma cavity so that it mimics a bicornuate gography.

characterized

as hyaline,

cystic,

myxoma-

tous, fatty, or carneous. These tumors are estrogen dependent and usually regress after menopause. They are usually multiple. Leiomyomas occur most commonly in the myometrium of the uterine corpus, occasionally in the lower uterine

segment,

and rarely (3%) in the cervical

region. According

to

theIr location with respect to the layers of the uterus, myomas are classified as submucous (under the endometrium), mural (within the myometrial wall of the uterus), or subserosal (projecting out of the uterine wall and covered by serosa).

Many lesions submucous

are in a combined and

location

(e.g., having

both

mural

components). This classification is and clinical purposes, because the and the treatment options vary accord-

useful for both imaging signs and symptoms

subserosal

Plain

in the differential

pedunculated

fibroid

standpoint,

diagnosis; may mimic

1992

April

location

is

for example,

a

an adnexal

mass.

may deform the uterine uterus on hysterosalpin-

Radiography

Plain radiography not show

of the abdomen

the uterine

Ieiomyoma

gone calcific degeneration. is more

common

with pedicles, Occasionally,

with

and pelvis often does

unless

the tumor

has under-

This type of degenerative

subserosal

lesions,

especially

change tumors

and in Ieiomyomas in postmenopausal women. a large, nonspecific soft-tissue mass will be

seen indenting the dome of the bladder or compressing the ureters at the pelvic brim, sometimes with dilatation of the

Fig. 4.-Transvaginal sonogram shows large hypoechoic mass in endometrial cavity (arrows).

‘

....

..-.,

4

Fig. 5.-Transvaginal

‘: ‘#{149}‘s,

endometrial

-

cous fibroid (M). Posterior eated (arrows).

‘

Fig. 6.-Transverse sonogram through fundal subserous myoma during third trimester of pregnancy shows signs of degeneration. Echo texture is heterogeneous, are present (arrows).

and several

echo (cursors)

cystic

spaces

Fig. 7.-Sagittal

sonogram

at 31 weeks’

ges-

tation shows large fibroid (black arrows) in lower uterine segment posteriorly. Note heterogeneous echo texture and cystic spaces (white arrow). Persistent transverse fetal lie necessitated cesarean

section. Lower uterine segment and cervical fibroids are associated with increased use of ccsarean delivery due to malpresentation and obstructed

labor.

B

=

bladder,

F

=

fetus.

Fig.

8.-Transverse

sagittal sonogram shows draped over submumargin of mass is delin-

transabdominal

sono-

gram shows lobulated hypoechoic mass (arrows) inseparable from left side of uterine body (u). At surgery, a subserosal myoma extending into left broad ligament was found.

AJR:158,

IMAGING

April 1992

OF UTERINE

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upper urinary tract. Irregular coarse calcifications in the pelvis are most often caused by uterine leiomyomas. Occasionally, circumferential

calcification

of the lesion

may occur

(Fig. 1).

LEIOMYOMAS

nancy

Sonography

is ideal

to confirm

clinically

suggested

uterine

fibroids. The most common sonographic appearance is of a hypoechoic (Fig. 2) or heterogeneous uterine mass. When multiple

small

leiomyomas

are

present,

sonography

may

merely show globular small mural Ieiomyomas endometrial echo (Fig. myoma will be seen as (Fig.

4), with

uterine enlargement. Submucous or may distort the normally linear central 3). Occasionally, a large submucous a mass within the endometrial cavity the endometrial echoes draped over the mass

(Fig. 5). The sonographic

texture

of Ieiomyomas

depends

with distal acoustic

calcific

degeneration.

Fig.

shadowing

Cameous

9.-Hysterosalpingogram

shows

are quite common

degeneration

submu-

cous fibroid as large polypold filling defect (open arrows) in enlarged uterine cavity. Also seen is mucosal irregularity (solid arrows), which may be due to additional small submucous fibroids or endometrial hyperplasia shown in Fig. 4.)

(Sonogram

of this patient

is

Fig. 10.-Hysteroselpingogram shows normalcavity with irregular central filling defect and venous myometrial intravasation at site of attachment to right uterine wall (arrow). A submucous myoma was found at surgery in addition to numerous other mural fibroids not seen on hys-

sized uterine

teroulplngography. shown in Fig. 5.)

Fig. 11.-Submucous

(Sonogram

of this patient is

myomas resembling

en-

dometrial polyps. A, Hysterosalpingogram shows numerous filling defects in uterine cavity. B, Hysterosalpingogram obtained after hysteroscopic myomectomy shows uterine cavity has a more normal appearance, with mucosal irregularity (black arrows) and diverticulum (white arrow), an unusual postsurgical finding.

during

severe

pain and appear

sonographically

as

are associated

with

a higher

frequency

of cesarean

sections and retained placentas [2] (Fig. 7). Pedunculated subserosal leiomyomas extend laterally outward between the folds of the broad ligament (intraligamentary), simulating an adnexal mass (Fig. 8). Transvaginal sonography provides detail that surpasses that of transabdominal sonography. Transvaginal imaging can detect very small lesions and provides better differentiation of a submucous from a mural lesion, as both may produce

distortion limited

of the endometrial

field

of view,

subserosal

echo.

However,

be missed,

and the transvaginal

approach

conjunction

with

sonography.

transabdominal

because

or pedunculated

fibroids

should

of a may

be used in

on

the relative ratio of fibrous tissue to smooth muscle and on the presence and type of degeneration. Hence, Ieiomyomas may be minimally ectiogenic; irregular anechoic areas are seen if cystic degeneration is present. Clusters of high-level echoes

may cause

a heterogeneous pattern with cystic spaces within the fibroid [1] (Fig. 6). Fibroids located in the lower uterine segment and cervix

Sonography

801

with

preg-

HvefrnIninn,nranhv

Hysterosalpingography is considered identification of a submucous leiomyoma.

can be seen as smooth multiple

the gold standard for Submucous lesions

(Fig. 9) or irregular

(Fig. 1 1) filling defects

with or without

(Fig. 10), single or gross

distortion

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802

KARASICK

ET AL.

Fig. 12.-Importance of early radiograph of uterine cavity in hysterosalpingography. A, Early filling radiograph shows large submucous fibroid in left corpus with lobulated (arrows). B, On later radiograph, mass is nearly obscured by dense contrast material.

AJR:158,

margins

April 1992

Fig. 13.-Hysterosalpingogram shows fundal submucous fibroid (open arrows) associated with venous myometrial intravasation of contrast medium (solid arrows). Later radiographs showed filling of pelvic veins; together with fundal mass

effect, these findings suggest a fibroid rather than adenomyosis.

Fig. 14.-Hysterosalpingogram shows small submucous fibroid (arrow) simulating endome-

Fig. 15.-Hysterosalpingogram lar enlargement of uterine

trial polyp in lower uterine segment of anteflexed

fibroids.

uterus.

of the uterine cavity. Attention to technique is important in the evaluation of leiomyomas; early filling radiographs of the uterus along with oblique views should be used (Fig. 1 2). The endometrium overlying some submucosal tumors is often thin or necrotic causing mucosal irregularity and venous myometrial intravasation (Fig. 1 3). Early vascular intravasation can

resemble

adenomyosis,

but later films may show opacification

of pelvic veins.

Small

to differentiate

from endometrial

Submucous

myomas,

submucous however,

leiomyomas

polyps usually

may be difficult

(Figs. 1 1A and 14). alter the uterine

con-

cavity

shows globudue to mural

Fig. 16.-Large mural/submucous fibroid. Hysterosalpingogram shows large soft-tissue mass displacing uterus (U) to left. Crescentic impression on uterine cavity suggests a submucous component. Note elevation and draping of right fallopian tube (arrows) over mass.

tour and size, whereas polyps are usually seen as a filling defect in an otherwise normal uterine cavity. Mural leiomyomas often enlarge the uterine cavity in a globular fashion (Fig. 1 5), and when they have a submucous component, they may produce an enlongated or crescentic configuration to the uterine cavity (Fig. 1 6). Fundal Ieiomyomas can cause an increase in the distance between the two uterine cornua, simulating a bicornuate uterus (Fig. 1 7). Subserosal leiomyomas usually have no definite signs on hysterography, but they can be large and be seen as soft-tissue masses that

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AJR:158,

April

IMAGING

1992

Fig.

17.-Hysterosalpingogram suga bicomuate uterus except for small nodular filling defect and focal mucosal

gests

irregularlty(arrow), once of fundal surgery.

which submucous

is a clue to prosfibroid found at

Fig. 20.-CT scan shows uterus (U) with heterogeneous tiple myomas are suggested,

OF UTERINE

enlarged lobulated enhancement. Mulbut their location Is

Fig. 21.-CT scan of pelvis (same patient in Fig. 2) shows lobulated uterus (arrows). discrete mass can be discerned. (Sonogram this patient Is shown in Fig. 2.)

deform the uterine cavity as well as compress, occlude the fallopian tubes (Figs. 18 and 19).

displace,

and

The most common CT findings of leiomyoma are a deformed uterine contour and an enlarged uterus (Fig. 20). Leiomyomas usually display uniformly solid consistency (Fig. 21), but they may be heterogeneous (Fig. 20) because of hyaline or cystic degeneration [3]. The presence of calcificasign

a coarse

of leiomyoma

(Fig.

dystrophic 22).

type,

A necrotic

is the most or degenerating

MR

Fig.

shows

19.-Hysterosalpingogram

cous myoma in left corpus (black

of filling

of fallopian

tubes.

Fig. 22.-CT scan shows of coarse, dense calcifications

as

No of

myoma

arrows).

typical appearance in uterine fundal

(arrows).

Imaging

MR imaging provides excellent visualization and localization of uterine Ieiomyomas [4]. Usually the lesions are well circumscribed and have medium-intensity signal similar to that of

CT

usually

submuPresence of large pelvic soft-tissue density suggests additional subserosal fibroids (white arrows). Note lack

Fig. 18.-Hysterosalpingogram shows large leftsided subserosal fibroid delineated by intraperitoneal contrast material superiorly (small solid arrows). Note deviation of uterus to right (large solid arrow) and stretching of left fallopian tube (open arrows).

not well defIned. MR in this patient clearly delineated their mural location.

tion,

803

LEIOMYOMAS

specific leiom-

yoma may be seen as a low-attenuating mass in the uterus. Rarely, a leiomyoma may become infected and its central core filled with gas or purulent fluid.

adjacent myometrium on Ti -weighted images; on T2weighted images (e.g., 1 500/40 [TR/TE]), they usually have a homogeneous low-intensity signal (Fig. 23). Degenerating leiomyomas have various nonspecific MR appearances ranging from medium to high signal on Ti -weighted images to a heterogeneous,

on T2-weighted multiple

myomas,

mostly

images

high

signal

in the area

(Fig. 24). In patients

MA, with

its multiplanar

of degeneration

with large or

capability,

is often

the best study to precisely delineate the location of each mass (Figs. 23 and 25-27). In particular, MR images are ideal to show the proximity of a myoma to the bright endometrial

KARASICK

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804

ET AL.

AJR:158,

April

1992

Fig. 23.-Sagittal MR image (1500/40) shows numerous mural myomas (m). Other images confirmed displaced but intact endometrial echo. (CT scan of this patient is shown In Fig. 20.)

Fig. 24.-Large

submucous

fibroid

with cystic

degeneration. Midsagittal MR image (1500/40) of uterus shows large submucous fibroid (arrows) bulging into high-signal-intensity endometrial cayity (e). High signal intensity (asterisk) in center of

fibroid indicates cystic degeneration. Additional myomas of low signal intensity are seen in cervix (f) and posterior

corpus

(F).

Fig. 25.-A, Hysterosalpingogram shows large polypoid filling defect (arrows) in cervical region. Cervical fibroids may be difficult to visualize unless they protrude into cervical canal. B, Sagittal MR image (1500/40) clearly depicts myoma (asterisk) in anterior cervix of retroverted uterus (solid arrows). High-intensity rim (open arrow) most likely is due to vascular congestion.

A

B

Fig. 26.-A, Sagittal MR image (1500/40) shows multiple low-signal-intensity masses in submucous (asterisk), mural (m), and subserous (s) lo-

cations. Note that submucous myoma impinges on endometrial signal. Another submucous myoma found at surgery was seen on other MR images. B, Hysterosalpingogram shows only two sub-

mucous myomas (m).

AJR:158,

IMAGING

April 1992

Fig. 27.-Advantage

of MR fordefining

OF UTERINE

805

LEIOMYOMAS

location

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of large fibrold. A, Transverse

transabdomlnal sonogram shows mass (arrows), but its ic cation is uncertain. B, Sagittal MR image (1500/40) shows intact endometrium with huge exophytic subserosal large,

myoma arrows). ation.

inhomogeneous

(solid

arrows)

arising

from

hindus

(open

Mixed signal intensity is due to degener-

cavity (Fig. 24). Some Ieiomyomas are surrounded intensity rim on T2-weighted images (Fig. 25B),

resulting

from local vascular

congestion

by a highmost

likely

[5].

the leiomyoma in response to medical nadotropin releasing hormone agonist.

superior

to sonography

operative with

multiple

localization or large

treatment with a goMA imaging may be

and hysterosalpingography of Ieiomyomas,

particularly

for prein patients

tumors.

Summary There is no single correct approach to evaluating uterine Ieiomyomas. Accurate assessment of the number, size, and location of Ieiomyomas, especially when myomectomy is planned, is important because it often influences the type of surgical approach. CT is not a first-line imaging study; however, it often shows leiomyomas in asymptomatic patients. Hysterosalpingography and transvaginal sonography are particularly useful in the diagnosis of submucous leiomyomas. This is fundamentally important because these tumors are often missed on clinical examination, at dilatation and curettage, and on transabdominal sonography, especially if the leiomyoma is small and the patient obese. Transvaginal sonography enables follow-up study of growth or shrinkage of

REFERENCES 1 . Altchek A. Management of uterine lelomyomata. In: Altchek A, Deligdisch L, eds. The uterus. New York: Springer-Verlag, 1991:344-365 2. Lev-Toaff AS, Coleman BG, Arger PH, Mintz MC, Arenson RL, Toaff ME. Leiomyomas in pregnancy: sonographic study. Radiology 1987;164: 375-380 3. Casillas J, Joseph RC, Guerra JJ. CT appearance of uterine leiomyomas. RadioGraphics 1990;10:999-1007 4. Dudiak CM, Turner DA, Patel 5K, Archie JT, Silver B, Norusis M. Uterine leiornyomas in the infertile patient: preoperative localization with MR imaging versus US and hysterosalpingography. Radiology 1988;167: 627-630 5. Mittl RL, Yeh 1-Tien, uterine leiomyomas

1991;180:81-84

Kressel HY. High-signal-intensity on MR images: pathologic

rim surrounding correlation. AJR