A case of
müllerianchoristoma
in rectovaginal septum:Developmental
Endocervicosis and
Developmental Endometriosis
–Müllerianosis
Yaqi Fang1#,Jun Li2#,Fang
Zhang1,Yunqian Chen1,Zhongfeng
Liu1*
1Department of Ultrasound, Yantai Affiliated Hospital
of Binzhou Medical University, Yantai, Shandong 264100, China.
2Department of Radiology, Yantai Affiliated Hospital
of Binzhou Medical University, Yantai, Shandong 264100, China.
#These authors contributed equally to this study.
*Corresponding author: Zhongfeng Liu, No. 717, Jinbu
Street, Department of Ultrasound, Yantai Affiliated Hospital of Binzhou
Medical University, Yantai, Shandong 264100, China. Email:
liuyichaoxy@163.com
CASE report
The presence of Müllerian choristoma
in the rectovaginal septum, which containing developmental
endocervicosis and developmental endometriosis (müllerianosis), has not
been documented in any literature.
In
this case, we present a patient with
heterotopic endocervical tissue and
endometrium in the rectovaginal
septum.
Ultrasound and MRI revealed a lesion within the rectovaginal septum. The
final microscopic diagnosis and immunohistochemistry confirmed
müllerianosis: developmental endocervicosis and developmental
endometriosis. We conclude that our patient has a benign
müllerianchoristoma (müllerianosis) with a lesion similar to those
previously described by Marwan Habiba[1] and
Ronald E.Batt et al[2], except for its location.
To our knowledge,this is the first documented case of
müllerianchoristoma inrectovaginal septum.
Müllerianosis may be defined as an
organoid structure of embryonic origin that incorporated within other
normal organs during organogenesis[3]. A
36-year-old patient, gravida 1 para 1, has been experiencing bloody
stool and constipation for the past two years.A transvaginal scan was
performed using a head scanning probe. The ultrasound examination
revealed an echo reflection in the intrauterine cavity that resembled an
endometrial polyp, as well as endometriosis-like echoes in the right
ovary. Furthermore, the scan detected a pelvic effusion and an uneven
high echo clump in the rectovaginal septum.
The transvaginal biplane ultrasound transducer was used to scan the
lesions in the rectovaginal septum. A hyperechoic structure resembling
’Pleurotus eryngii’ was detected in the rectovaginal septum (Fig.1).
This structure measured approximately 4.98cm in length and consisted of
a ’pileus’ and a ’stipe’. The
’pileus’ was positioned leaning forward and in close proximity to the
middle part of the posterior vaginal wall (about 0.27cm away from the
posterior vaginal wall), while its hollow ’stipe’ tilted backward and
downward, opening between the anocutaneous line and the rear of the
perineum. The ’pileus’ is surrounded by a hyperechoic cyst wall, which
is about 0.1cm thick. The interior of the ’pileus’ contains multiple
polyp-like structures with slightly hyperechoic reflections.
The area between the ’pileus’ and
the hyperecho cyst wall is filled with an
anechoic zone with poor sound
transmission. Multiple thin-walled anechoic areas with distinct
boundariesare scattered in the
’pileus’.The polypoid echo and the muscle fascicle-like ’stipe’ echo
extend towards the front of the external opening of the anal
canal. CDFI reveals that both the
polypoid echo and the ’stipe’ echo
exhibit rich blood flow signals(Fig.2). One of these vessels is
connectedto thevessels surrounding the anal canal.After injecting
sterile ultrasound gel, an increase in the presence of small bubble
anechoic areas can be observed between the ’pileus’ and the polyp-like
echo.A double-lumen urethral
catheter was inserted through the end opening of the ’stipe’,while
simultaneously inserting a catheter into the anal canal. The opening of
the lesion was found to be approximately 0.2cm away from the front of
the external opening of the anal canal (Fig.3).
MRI
revealedabnormal signals in the rectum,consistent with pelvic
endometriosis. Electronic colonoscopy detected a 2cm submucosal bulge in
the rectum, located approximately 4cm away from the
anus.The
bulge was palpable and could be moved upon touch.
After administering general
anesthesia, it was observed that the polypoid mass had
prolapsed between the rear of the
perineal body and the anal skin
line. The lesion was able to recover
to its original
position.During
laparoscopic exploration of the pelvic cavity,
multiple scattered endometriosis
lesions were observed within the
pelvic cavity.A sinus was detected
between the rectum and vagina during the digital rectal examination. The
sinus was located 1cm away from the anal verge. Based on these findings,
the patient was diagnosed with pelvic endometriosis.
Histological sections (Fig.4) of the
specimen revealed two types of epithelial components in the examined
polypoid tissue: squamous epithelium and glandular epithelium,
consistent with the characteristics of Mullerian epithelium.
Immunohistochemical
examinations found that the epithelial cells exhibited diffuse
expression of PAX-8, and both their histomorphology and immunomarkers
were consistent with those of cervical glandular epithelium.
Immunohistochemistry analysis also
revealed SMA expression. The
glandular cells in the cyst wall exhibited a higher proportion of cell
nucleus, which were pen-shaped and located at the bottom of the cells,
resembling Mullerian epithelium.The positive expression of CD10 in
immunohistochemistry supported that these glands and the interstitium
shared similar characteristics with the endometrium.
The histological analysis and
immunohistochemical examinations revealed the presence of ectopic
endocervixand endometrium within the soft tissues.Based on this,we
concluded that this case was müllerianosiscontaining developmental
endocervicosis and developmental endometriosis.
DISCUSSION
Endometriosis
is a prevalent benign illness defined by the presence of endometrial
glands and stroma outside of the uterine cavity, primarily
on the ovary, pelvic peritoneum, and rectovaginal
septum[4].This case strongly supports the theory
ofFour DevelopmentalMüllerian Diseases proposed by Ronald E. Batt et
al[2].According to this theory, developmental
adenomyosis, endometriosis, endosalpingiosis, and endocervicosis are
referred to as the 4 developmentalmüllerian
diseases[2]. In this case, the lesion was found in
the rectovaginal septum, with no direct
communications with the endocervix,
endometrium, or endosalpinx.
Immunohistochemistry analysis also
revealed SMAexpression. Bundles of differentiated smooth muscle tissue
were observed surrounding the cervical stromal cells and cyst wall-like
structures,suggesting that epithelial cells induce the simultaneous
development of surrounding smooth muscle during the formation of ectopic
tissue. Additionally, epithelial cells contribute to the development of
smooth muscle tissue during embryonic development.These findings support
that this is a developmental (embryonic origin) müllerian disease rather
than an acquired müllerian disease.
Our
hypothesis is that the hyperechoic cyst wall surrounding the ’pileus’ is
comparable to the concept of ’peritoneal pocket’described by Batt R E in
1990[5] and 2007[3] . The
term ’peritoneal pocket’ was proposed to represent an organoid
structure, where the floor of this structure could be grasped and turned
inside out for excision. In this case, a similar eversion state was
observed.The cells in the cyst wall
surrounding the ’pileus’ exhibit characteristics of Mullerian
epithelium.
The presence of bloody stool and constipation can be attributed to the
developmental endometriosis of the cyst wall. This condition is
influenced by hormones and undergoes periodic shedding and bleeding. The
blood passes through the tube that opens between the anocutaneous line
and the perineal body, leading to the presence of bloody stool.
Additionally, constipation can be caused by straining to defecate and
the presence of everted multiple polyps that block the external anal
opening.
In this case, müllerianosis lesion is located in the lower-middle part
of the rectovaginal septum at the end of the midline of the human body,
which is consistent with the distribution of lesions described by Batt
RE[2, 6],Hattori H[7],
Andronik IshkhanKalayjyan[8],
Pansera[9],Buerger[10],Xueyan
Chen[11],and others.Based on Ludwig’s
theory[12], Batt R.E predicted that no cases of
endocervicoticchoristomas will be found above the
diaphragm[6]. Conversely, it is predicted that no
cases of endosalpingiosischoristomas will be found below the pelvic
diaphragm.Whether this prediction can be established requires the
discovery of new cases for
verification.