Uterus-like mass of ovarian ligament: Image diagnosis and management by laparoendoscopic single-site surgery.

Abstract

Uterus-like mass composed of a cavity lined by mucosa resembling endometrium and surrounding smooth muscle layer simulating myometrium is an extremely rare disease entity of which the histogenesis is presently unknown. A 39-year-old, gravida 2, para 2, woman presented with sudden onset of lower abdominal pain and was found to have left adnexal mass with unusual image diagnostic appearance. The adnexal mass arising from the left ovarian ligament was excised by laparoendoscopic single-site surgery. Histopathological diagnosis was uterus-like mass of ovarian ligament.

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Uterus-like mass of ovarian ligament: Image diagnosis
and management by laparoendoscopic single-site surgery
Akihiro Takeda, Sanae Imoto, Masahiko Mori, Junko Yamada and Hiromi Nakamura
Department of Obstetrics and Gynecology, Gifu Prefectural Tajimi Hospital, Gifu, Japanjog_16911..5
Abstract
Uterus-like mass composed of a cavity lined by mucosa resembling endometrium and surrounding smooth
muscle layer simulating myometrium is an extremely rare disease entity of which the histogenesis is presently
unknown. A 39-year-old, gravida 2, para 2, woman presented with sudden onset of lower abdominal pain
and was found to have left adnexal mass with unusual image diagnostic appearance. The adnexal mass
arising from the left ovarian ligament was excised by laparoendoscopic single-site surgery. Histopathological
diagnosis was uterus-like mass of ovarian ligament.
Key words: image diagnosis, laparoendoscopic single-site surgery, ovarian ligament, uterus-like mass.
Introduction
Uterus-like mass composed of a cavity lined by mucosa
resemblingendometrium
smooth muscle layer simulating myometrium is an
extremely rare disease entity of which the histogenesis
is presently unknown.1–13As uterus-like mass possesses
well-organized structure resembling normal uterine
corpus, it should be carefully differentiated from
extrauterine adenomyoma, which lacks a uterus-like
organization.8Although uterus-like mass has been
known to arise in the ovary1,2as well as in the extrao-
varian sites,3–13its development in ovarian ligament has
never been described. In the present report, image
diagnostic features of a uterus-like mass arising from
ovarian ligament and its successful excision by tran-
sumbilical laparoendoscopic single–site (LESS) sur-
gery14are described with a review of the relevant
literature.
andsurroundingthick
Case Report
A 39-year-old, gravid 2, para 2, woman without previ-
ous disease history had sudden onset of left lower
abdominal pain. She did not have any severe
menstruation-relatedsymptoms,
norrhea. Pelvic magnetic resonance imaging (MRI)
revealed a well-defined adnexal mass measuring
3.8 ¥ 3.5 ¥ 3.7 cm with cystic cavities in the left adnexal
region (Fig. 1a,c, arrow). The left ovary (Fig. 1a, arrow-
head) and uterus were normal (Fig. 1b,d, arrow). Drip
infusion pyelography and computed tomography (CT)
showed normal urinary system. Tumor marker (alpha-
fetoprotein,carcinoembryonicantigen,CA19-9,CA72-4
and SCC) values were normal except for slightly
elevated serum CA125 level (84.1 U/mL).
Under the diagnosis of adnexal mass with complex
structure, isobaric (gasless) LESS surgery was per-
formed according to the procedure as previously
suchas dysme-
Received: May 2 2011.
Accepted: May 21 2011.
Reprint request to: Dr Akihiro Takeda, Department of Obstetrics and Gynecology, Gifu Prefectural Tajimi Hospital, 5-161
Maebata-cho, Tajimi, Gifu 507-8522, Japan. Email: gyendoscopy@gmail.com
Conflict of Interest: There were no conflicts of interest relating to this study.
Funding: No funding was sought for the purpose of this study.
doi:10.1111/j.1447-0756.2011.01691.x
J. Obstet. Gynaecol. Res. 2011
© 2011 The Authors
Journal of Obstetrics and Gynaecology Research © 2011 Japan Society of Obstetrics and Gynecology
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described.14Briefly, under endotracheal general anes-
thesia, a 2.5-cm midline umbilical skin incision was
made and carried down into the peritoneum. An
Alexis wound retractor (Applied Medical, Rancho
Santa Margarita, CA, USA) was placed in position
through the umbilical incision. The abdominal wall was
then lifted by the Subcutaneous Lift System (Mizuho,
Tokyo, Japan). A rigid 5-mm, 30-degree EndoEYE lap-
aroscope (Olympus, Tokyo, Japan) and multiple con-
ventional laparoscopic instruments were introduced
transumbilically through a wound retractor that
secured a wide orifice for manipulation.
Underlaparoscopic
circumscribed left adnexal mass was identified (Fig. 2a,
arrow).Withoutdirectconnectiontotheuterinecorpus,
this mass lesion arose from the left ovarian ligament.
Scattered peritoneal endometriotic lesions were noted.
The uterus and right adnexa were grossly normal.
Although severely compressed by the adnexal mass
(Fig. 2b, arrow), the left ovary was clearly separated
observation,thewell-
ab
cd
Figure 1 (a) Axial T2-weighted magnetic resonance image (MRI) of the uterus-like mass with cystic cavities in the left
adnexal region (arrow). Adjacent to the uterus-like mass, a normal left ovary (arrowhead) was identified; (b) Axial
T2-weighted MRI of the uterus with normal structure (arrow); (c) Sagittal T2-weighted MRI of the uterus-like mass in the
left adnexal region (arrow); (d) Sagittal T2-weighted MRI of the uterus with normal structure (arrow).
A. Takeda et al.
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from it. The adnexal mass (Fig. 2c, arrow) was excised
concomitantlywiththeleftadnexausingLigasureAtlas
(Covidien Japan, Tokyo, Japan). The excised tissue
weighed 18 g. Surgical duration was 81 min. Intraop-
erativebloodlosswas100 mL.Thepostoperativecourse
was uneventful and no recurrence was noted 1 year
after surgery.
On the cut surface, the excised mass (Fig. 2d, arrow)
had a cavity surrounded by a thick solid structure. The
cystic portion contained dark brown material. The left
fallopian tube appeared to be normal. Microscopically
(Fig. 3a), the adnexal mass was composed of a cavity
lined by epithelium (E) and stroma (S), and the layer of
smooth muscle cells (M), and showed well-organized
structure similar to normal uterine corpus. Immuno-
histochemical analysis on the characteristics of the cells
forming the mass lesion was performed using the anti-
bodies against cytokeratin (Fig. 3b), CA125 (Fig. 3c),
a-smooth muscle actin (a-SMA) (Fig. 3d), CD10
(Fig. 3e), estrogen receptor (ER) (Fig. 3f) and progest-
erone receptor (PR) (Fig. 3g). Summarized immunore-
activity of each cellular component to tested antibodies
is shown in Figure 3h. Based on histological findings of
the present mass lesion, this lesion was diagnosed as a
uterus-like mass of the left ovarian ligament.
Discussion
Uterus-like mass is an extremely rare benign pathologi-
cal entity of uncertain histogenesis.1–13Although the
ovary is the initially described1and most commonly
reported site for development of a uterus-like mass,1,2
the disorder has been known to occur in the various
genital and extragenital locations.3–13When definitive
diagnosis of uterus-like mass is made, it should
be differentiated from extrauterine adenomyoma.8
Uterus-like mass possesses mature and well-organized
structure composed of a cavity lined by mucosa resem-
bling endometrium and surrounding thick smooth
muscle layer simulating myometrium, whereas extrau-
terine adenomyoma lacks such mature structure. From
ab
cd
Figure 2 Excision of a uterus-like mass arising from the left ovarian ligament by isobaric laparoendoscopic single-site
surgery. (a) Uterus-like mass (arrow) was developed from the left ovarian ligament; (b) The left ovary was clearly separated
from uterus-like mass (arrow); (c) The uterus-like mass was excised with Ligasure Atlas (Covidien Japan, Tokyo, Japan)
after adhesiolysis; (d) Macroscopic appearance of the cut surface of the uterus-like mass (arrow) concomitantly excised
with the left ovary and fallopian tube.
Uterus-like mass of ovarian ligament
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this aspect, the present report is the first published case
of uterus-like mass developing in ovarian ligament.
There have been limited descriptions on the imaging
characteristics of uterus-like mass.7,9,10,12,13In particular,
MRI of uterus-like mass has been reported on limited
occasions.9On preoperative MRI study of the present
case, a definitive diagnosis of the uterus-like mass was
not obtained due to our limited knowledge about this
disorder. As retrospective evaluation of MRI clearly
indicates that the present adnexal mass possessed the
characteristic structures similar to those of uterus, the
images shown in the present report would be informa-
tive for future reference to diagnose uterus-like mass.
For management of uterus-like mass, laparoscopic
excision has been performed only recently and in
limited cases.9,11,13In the present case, the newly
emerged LESS procedure14was utilized for excision of
the uterus-like mass for the first time in the literature.
Some difficulties in adhesiolysis and hemostasis were
encountered in the present case due to lack of triangu-
lation in LESS procedure. However, as minimally inva-
sive excision would be beneficial for the patient,
laparoscopic management would be desirable in
similar future cases if applicable.
Regardingthehistogenesisoftheuterus-likemass,1–13
three hypotheses have been proposed: (i) Müllerian
duct fusion defect; (ii) metaplasia; and (iii) heterotopia
theories. The metaplastic theory has been proposed to
be the most probable histogenesis of uterus-like mass.
This theory is based on the idea that uterus-like mass
may arise from the peritoneal mesothelium and its sub-
jacent connective tissue that retain the ability to dupli-
cateMüllerianductstructures.1,4–8,10–13Thesetissuesmay
retain the potential to produce uterus-like Müllerian
structures under the influence of sex steroid hormones.
Although immunohistochemical analysis of ER and PR
abh
c
fg
de
Figure 3 Histological findings of the uterus-like mass. (a) The uterus-like mass showed mature histological structure
composed of mucosa resembling normal endometrium, and surrounding layer of myometrial cells (HE); (b) Positive
cytokeratin (AE1/AE3) in the cytoplasm of glandular epithelial cells of the uterus-like mass; (c) Positive CA125 in
cytoplasm of glandular epithelial cells of the uterus-like mass; (d) Positive a-smooth muscle actin in the cytoplasm of
stromal and myometrial cells of the uterus-like mass; (e) Positive CD10 in the cytoplasm of stromal cells of the uterus-like
mass; (f) Positive estrogen receptor in the nuclei of the epithelial, stromal and myometrial cells of the uterus-like mass; (g)
Positive progesterone receptor in the nuclei of the epithelial, stromal and myometrial cells of the uterus-like mass; (h)
Summarized immunoreactivity of each cellular component of the uterus-like mass to antibodies. a-SMA, a-smooth
muscle actin; E, epithelial cells; ER, estrogen receptor; M, myometrial cells; S, stromal cells; PR, progesterone receptor. All
bars, 200 mm.
A. Takeda et al.
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in the cellular component of uterus-like mass is still
limited in the published work,8positive immunoreac-
tivity for ER and PR in the nuclei of glandular, stromal
and myometrial cells of uterus-like mass in the present
case support the idea that the uterus-like mass could
arise through metaplasia of peritoneal mesothelium in
responding to stimuli of ovarian sex steroid hormones.
In the present case, the patient had neither a struc-
tural uterine abnormality consistent with Müllerian
fusion defect nor congenital urinary tract abnormalities
despite extensive imaging studies, which included
ultrasonography, MRI, CT and drip infusion pyelogra-
phy. Thus, the occurrence of metaplasia of peritoneal
mesothelium and its subjacent connective tissue under
the influence of sex steroid hormone fits well with our
observations in the present case of uterus-like mass
arising from the ovarian ligament.
In conclusion, uterus-like mass is a rare disorder that
needs further clarification of its histogenesis as well as
disease entity. Uterus-like mass should be included in
the differential diagnosis of a mass lesion that has a
well-defined structure with cystic cavity on pre-
operative imaging workup. Minimally invasive man-
agement would be beneficial to the patient when
surgical excision of a uterus-like mass is considered.
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Uterus-like mass of ovarian ligament
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Journal of Obstetrics and Gynaecology Research © 2011 Japan Society of Obstetrics and Gynecology
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