AJR 2004; 182:1531-1533
© American Roentgen Ray Society
Sonographic, CT, and MRI Findings of Endometrial Stromal Sarcoma Located in the Myometrium and Associated with Peritoneal Inclusion Cyst
U
ur Toprak1,
E
ref Paaolu,
M. Alp Karademir and
Mutlu Gülbay
1 All authors: Department of Radiology, Ankara Numune Education and Research
Hospital, Sihhiye, Ankara TR-06100, Turkey.
Received April 16, 2003;
accepted after revision October 21, 2003.
Address correspondence to U. Toprak.
Introduction
Uterine sarcomas such as leiomyosarcoma, endometrial stromal sarcoma, and
mixed müllerian tumor constitute 2–5% of all uterine malignancies
[1]. Endometrial stromal
sarcoma, however, constitutes fewer than 10% of all uterine sarcomas
[1]. Depending on the mitotic
activity rate, endometrial stromal sarcoma is classified as low- or high-grade
endometrial stromal sarcoma. Although half the low-grade endometrial stromal
sarcomas are limited to the endometrium, the other half shows focal, wormlike,
or diffuse multiple nodular permeations in the myometrium from endometrial
foci [1]. Despite a few cases
with masses of myometrial origin
[2], there have been no
previous reports of the radiologic appearance of primary myometrial
endometrial stromal sarcoma with diffuse and multinodular involvement of the
myometrium. This article presents a low-grade endometrial stromal sarcoma with
multiple nodular masses located in the myometrium and diffuse myometrial
permeation.
Case Report
A 24-year-old woman was admitted to the hospital because of a slowly
growing, tender mass in the lower abdomen and menorrhagia. The patient's
history revealed no previous genitourinary disease. She had been healthy until
10 months earlier when she began to have abdominal fullness and menstrual
irregularities. At physical examination, the uterus was enlarged. Laboratory
test findings, including tumor markers and hormone levels, were unremarkable.
The patient was referred to our radiology department with a presumed diagnosis
of leiomyomatosis.
Transabdominal sonography revealed a left cornual, myometrial complex
cystic mass with smooth borders that contained nodular solid areas and cystic
spaces with thick septations (Fig.
1A). Additionally, multiple small myometrial nodules with
hypoechoic peripheral rims were shown (Fig.
1B), some of which had centrally located cystic areas. Several
myometrial lesions were compressing the endometrium, but they had no clear
association with the endometrium. A left adnexal and extraovarian cystic
lesion with fine septations was displacing the left ovary. A simple ovarian
cyst was also present in the left ovary.
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Fig. 1A. —Endometrial stromal sarcoma and associated peritoneal
inclusion cyst in 24-year-old woman. Axial transabdominal pelvic sonogram
shows complex myometrial mass with cystic and solid components.
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Fig. 1B. —Endometrial stromal sarcoma and associated peritoneal
inclusion cyst in 24-year-old woman. Axial transabdominal pelvic sonogram
shows multiple, small, centrally hyperechoic cystic nodules (solid
arrowheads). Note also left ovarian cyst (open arrowhead) and
peritoneal inclusion cyst (arrows).
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Contrast-enhanced CT displayed heterogeneous enhancement of the solid
components and septations of the cornual complex cystic lesion and similar
enhancements in the small nodules (Fig.
1C).
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Fig. 1C. —Endometrial stromal sarcoma and associated peritoneal
inclusion cyst in 24-year-old woman. Axial contrast-enhanced CT scan shows
heterogeneous enhancement of solid components of myometrial nodules (solid
arrowheads) and left adnexal peritoneal inclusion cyst (open
arrowheads).
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After unenhanced T1-weighted MRI and T2-weighted MRI, contrast-enhanced
T1-weighted MRI was performed. Solid parts, septations of left cornual cystic
lesion, and small myometrial nodules were isointense with the myometrium on
unenhanced T1-weighted images and hyperintense on T2-weighted images.
Heterogeneous enhancement was also present after gadolinium administration
(Fig. 1D). The cystic component
of the cornual lesion had higher signal intensity than urine on T1- and
T2-weighted images. Some of the small myometrial nodules had hypointense
centers on both sequences. MRI revealed no clear association with endometrium
(Figs. 1D and
1E). A diffuse permeation from
adjacent myometrium leading to diffuse thickening at the right fallopian wall
was present, which was sustained throughout the broad and round ligaments and
extended to the peritoneum. The content of the left adnexal cystic lesion
displacing the left ovary was slightly more intense than the cystic lesion in
the left ovary (Fig. 1F).
Radiologic examination findings were suggestive of the adnexal cystic lesion's
being a peritoneal inclusion cyst.
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Fig. 1D. —Endometrial stromal sarcoma and associated peritoneal
inclusion cyst in 24-year-old woman. Coronal T1-weighted image obtained after
gadolinium injection shows heterogeneous enhancement of left cornual mass
(solid arrowheads) and other myometrial nodules (white
arrows). Note one nodule compresses endometrium (black arrow)
but is completely myometrial in origin. Diffuse thickening is also present at
right fallopian wall, which shows continuity with broad and round ligaments
and reaches peritoneum (open arrowheads).
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Fig. 1E. —Endometrial stromal sarcoma and associated peritoneal
inclusion cyst in 24-year-old woman. Coronal T2-weighted image obtained at
same level as D shows increased signal intensity of mass (solid
arrowheads) and nodules (white arrows) relative to that of
myometrium. Endometrial compression (black arrow) and right fallopian
wall invasion (open arrowheads), showing continuity with broad and
round ligaments, are also marked.
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Fig. 1F. —Endometrial stromal sarcoma and associated peritoneal
inclusion cyst in 24-year-old woman. Axial T2-weighted image shows signal
intensity of peritoneal inclusion cyst (solid arrowhead) to be
brighter than that of ovarian cysts. Note left ovarian simple cyst and right
ovarian follicle (open arrowheads).
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An endometrial curettage specimen showed no disease. Thus, total abdominal
hysterectomy was performed, and study of the pathologic specimen yielded the
diagnosis of a low-grade endometrial stromal sarcoma. No endometrial component
was detected. However, a lymphangitic invasion of the myometrial tissue
throughout the uterus, including the cervical myometrium, was present. The
neoplastic process penetrated the serosa and reached the peritoneum. The left
adnexal cyst was confirmed intraoperatively to be a peritoneal inclusion
cyst.
Discussion
Endometrial stromal sarcoma is a neoplastic process developing from
endometrial stromal cells. Neoplastic cells may originate from endometrial
tissue, but they may also originate from pathologic processes such as
adenomyosis and endometriosis
[3].
Endometrial stromal sarcoma leads to the same symptoms as those of any
other uterine sarcoma or endometrial carcinoma. More than half the cases occur
in premenopausal women, particularly those with low-grade endometrial stromal
sarcoma [1]. Endometrial
curettage may not yield a significant result for low-grade endometrial stromal
sarcoma because of its similarity to normal endometrial tissue
[4]. Endometrial biopsy results
were unremarkable in our patient, and in the radiologic studies lesions were
described as completely myometrial.
Although uterine sarcomas are described as aggressive neoplasms,
endometrial stromal sarcoma has a low potential for spreading. Although it is
more common in patients between ages 42 and 53, low-grade endometrial stromal
sarcoma tends to occur in a younger age group (mean, 39 years)
[1].
Endometrial stromal sarcoma can spread to the vagina, fallopian tubes,
uterine ligaments, ovaries, bladder, and ureters
[4]. In our patient, diffuse
myometrial permeation of the right fallopian tube extended to the broad and
round ligaments and invaded the peritoneum without any interruption.
Radiologic studies revealed no endometrial component, and endometrial
curettage was unremarkable.
Definitive diagnosis of any uterine sarcoma based on sonography alone is
not possible [5] because these
kinds of tumors may have nonspecific findings such as polypoid endometrial
masses, endomyometrial thickening, and adnexal masses. Accordingly, no
diagnostic sonographic finding was detected in our patient.
Uterine sarcomas have no specific tomographic feature to aid in the
differential diagnosis, and CT is mostly used to detect distant metastases and
stage the disease. Low-density mass with necrosis is the most common pattern
of uterine sarcomas [6]. In our
case, heterogeneously enhanced left cornual complex mass and multiple
contrast-enhanced small myometrial nodules with cystic centers were low-grade
endometrial stromal sarcoma lesions.
Tumoral lesion of the endometrial stromal sarcoma is isointense relative to
the myometrium on T1-weighted MRI and hyperintense on T2-weighted MRI.
Furthermore, it shows heterogeneous but prominent enhancement in
contrast-enhanced images because of its rich vascularity. In addition to the
lesions in the form of large masses with irregular margins, multiple nodular
mass formations and intramyometrial wormlike nodular extensions are frequently
seen. Marginal nodular lesion is a common finding and is representative of its
invasive character [7].
Leiomyomas can have variable appearances on MRI depending on cellularity
and the presence of cystic degeneration, necrosis, hemorrhage, and
calcification, and they are usually well demarcated
[7]. Thus, radiologic
differentiation could be possible before surgery. In our patient, tumoral
infiltration up to the peritoneum was not compatible with leiomyoma.
It is difficult to differentiate endometrial stromal sarcoma from
leiomyosarcoma even with MRI. Leiomyosarcomas have variable signal intensities
on T2-weighted images, and their masses display irregular margins
[2].
Endometrial cancer presents with endometrial masses that have intermediate
to low signal intensity on T1-weighted images and low signal intensity on
T2-weighted images, whereas signal intensity of endometrial stromal sarcoma is
higher on T2-weighted images. Unlike endometrial stromal sarcoma masses,
endometrial carcinoma masses are not well enhanced
[4].
Adenomyosis may affect the myometrium diffusely. Unless a hemorrhagic
complication supervenes, the lesion of adenomyosis is hypointense relative to
the myometrium on both T1- and T2-weighted MRI
[4].
Conventional treatment of endometrial stromal sarcoma is hysterectomy
[4]; thus, it was performed on
our patient. Chemotherapy and radiotherapy should be considered as other
treatment options.
Peritoneal inclusion cyst is diagnosed when an intact ovary has a cystic
appearance and often forms after the surgical procedures in the pelvis, but it
is also caused by endometriosis or pelvic inflammatory disease
[8]. Interestingly,
endometriosis can lead to endometrial stromal sarcoma as well as to peritoneal
inclusion cysts [3].
Nevertheless, neither the study of the pathologic specimen nor the history of
the patient showed endometriosis.
In conclusion, endometrial stromal sarcoma should be kept in mind in the
differential diagnosis of heterogeneously enhanced, complex cystic, and
invasive myometrial masses, particularly among the patient group of
premenopausal women.
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Introduction
Case Report
