Author Information
Parulekar SV*, Fernandes G**.
(* Professor and Head, department of Obstetrics and
Gynecology, ** Associate Professor, department of Pathology; Seth GS Medical
College & KEM Hospital, Mumbai, India)
Abstract
Endometrial stromal sarcoma is a very rare malignant tumor
of the uterus. Usually it is mistaken for a uterine leiomyoma clinically, and
the diagnosis is usually made after surgical removal. We present a case that
was suspected during myomectomy and was managed by hysterectomy. Histopathology
confirmed the diagnosis.
Introduction
Endometrial stromal sarcoma (ESS) is a very rare malignant
tumor of the uterus. It accounts for about 0.2% of all uterine malignancies.
Usually it is an intramyometrial tumor, and cannot be diagnosed clinically. Its
presence can be suspected by imaging preoperatively. We present an unusual case
that presented as a submucous polyp in the uterine cavity. This diagnosis was
suspected during a failed attempt at myomectomy, and was confirmed by
histopathology later.
Case Report
A 42 year old woman with two term deliveries in the past
presented with abnormal uterine bleeding for four months. She had prolonged and
excessive blood loss during menstruation and in between menses too. Her past
menstrual cycles had been regular and with moderate flow over 3 to 4 days. Her
last delivery had been 10 years ago. She did not use any contraception. General
examination showed moderate pallor. Her vital parameters were normal. Systemic
examination showed no abnormality. Gynecological examination showed uterus
enlarged to a size of about 12 weeks of gestation. The cervix was 2 cm open,
30% effaced. The vagina was normal. There were no pelvic or abdominal masses.
Abdominopelvic ultrasonography (USG) showed a 6.5 cm diameter polypoid mass
arising from the anterior wall of the endometrial surface of the uterus. There
was no lymph node enlargement or hepatic metastasis. Her blood sugar level,
hepatic and renal function tests, chest radiograph and electrocardiogram were
normal. Her hemoglobin level was 6 g/dL. She was transfused 4 units of packed
cells over 4 days. Polypectomy was undertaken under general anesthesia. The
posterior cervical wall was cut in the midline up to the internal os, so as to
enable enucleation of the polyp. The mass was spherical, more than 75% of it
projecting into the uterine cavity. There was no pedicle. The mass was held
with a tenaculum and a vulsellum. Its capsule was bluntly dissected by digital
pressure and attempt was made to dissect and enucleate it from its bed (figure 1). That
attempt failed. Its removal was attempted by holding it firmly and twisting it
clockwise. However it delivered piecemeal and could not be delivered in its
entirety. There was no bleeding from the mass left behind. A diagnosis of a
degenerated leiomyoma or a tumor like an ESS was made, the reason being the
inability to enucleate it despite ease of access. After closure of the
cervicotomy, the patient started bleeding vaginally, though not from the
cervical os. A uterine wall injury could not be ruled out. So an abdominal
hysterectomy was done. There was no uterine injury. The bleeding was from a cut
edge of the cervicotomy incision, which had not been diagnosed before. There
was no spread of the disease to the omentum, bowel, parietal peritoneum, pelvic
or paraaortic lymph nodes and liver. About one-third of the mass was seen to be
left behind, when the uterus was opened after the hysterectomy (figure 2). The
patient made an uneventful recovery.
Gross examination showed full thickness involvement of the
myometrium by the tumor, but serosa was intact.Histopathology of the tumor
(figures 3-6) showed sheets and tongues of neoplastic endometrial stromal cells
extensively invading the full thickness of the myometrium. The serosa was
intact. The tumor cells were monotonous in appearance, oval shaped, with
basophilic mildly atypical nuclei and scanty cytoplasm. A prominent delicate
arborising vasculature was seen throughout the tumor. The tumor cells resembled
proliferative endometrium and whorling of the neoplastic cells was seen around
the arterioles. 2-3 mitosis per 10 HPF were seen. No necrosis was seen. A
diagnosis of low grade endometrial stromal sarcoma was made.
Figure 1. Process of attempt at enucleation of the polyp after posterior cervicotomy.
Figure 2. Uterus cut open after abdominal hysterectomy to show partially enucleated tumor.
Figure 3. Microphotograph showing tongues of bluish
neoplastic endometrial stromal cells infiltrating and splaying the smooth
muscle of the myometrium. (H&E x100)
Figure 4. Microphotograph showing sheets of bluish
endometrial stromal cells seen extensively invading the myometrium. (H&E
x100)
Figure 5. Microphotograph showing tumor with monotonous oval
endometrial stromal cells with prominent delicate arborising vasculature.
(H&E x100)
Figure 6. Microphotograph showing high power view of the
neoplastic endometrial stromal cells resembling proliferative endometrium. Note
the whorling of tumor cells around the arterioles. (H&E x400)
Discussion
Endometrial
stromal sarcoma is a very rare malignant tumor of the uterus. As compared to
other malignancies, it tends to occur in younger women, the mean age being 50
years.[1] About 10 to 25% cases are premenopausal. [1] The term endometrial
stromal tumor is applied to tumors composed of cells that resemble endometrial
stromal cells of the proliferative endometrium. The new WHO classification
classifies endometrial stromal tumors into endometrial stromal nodule, low
grade endometrial stromal sarcoma and undifferentiated endometrial sarcomas. ESS
is said to be predisposed to by conditions like unopposed estrogen action,
tamoxifen therapy and polycystic ovarian disease.[2] Though the tumor primarily
is intramyometrial, it involves the endometrium in a number of cases.
Endometrial curettage in such cases may help make the diagnosis.[3,4]
The patients present with abnormal uterine bleeding (90%), uterine enlargement
(70%), pelvic pain, and/or dysmenorrhea. About 25% cases are asymptomatic. The
diagnosis of uterine leiomyoma is usually made. USG often erroneously shows
features of a leiomyoma or adenomyosis, as in our case. Transvaginal color
Doppler study shows low impedance flow as compared to other benign conditions
of the uterus. On magnetic resonance imaging, ESS shows myometrial invasion and
bands of low signal intensity in that area (due to worm-like permeation of
tumor cells) and spread by contiguity to fallopian tubes, ligaments, ovaries,
and along blood vessels.[5,6] However these tests are not done
routinely, because the clinical diagnosis of a leiomyoma or adenomyosis,
supported by USG, does not warrant these tests. If the mass appears to be a
polyp, there is even less indication for these tests, as in our case. That is
unfortunate, because about 50% cases have an extrauterine spread at the time of
the diagnosis.[1] Luckily, our patient had to undergo an immediate
hysterectomy because of incomplete removal of the mass and suspected uterine
injury. We did not perform bilateral salpingooophorectomy at that stage,
because we did not know it was a malignant tumor. Total hysterectomy was
adequate for her stage of the disease (stage I). Obtaining a frozen section
during the operation is not useful in making a diagnosis. If the condition is
strongly suspected, a biopsy may be taken before definitive treatment is
planned. It is easier when it is a submucosal mass that can be seen through the
cervix, as in the case presented. Prolonged follow up is required in all cases,
as about 30-50% cases develop recurrences in the pelvis and lower genital
tract, and sometimes in lungs years later.[7]
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Citation