2010, Volume 26, Number 1, Page(s) 085-088
Ovarian Heterotopic Pregnancy Clinically Mimicking Endometrioma
Nilüfer ONAK KANDEMİR1, Figen BARUT1, Gamze YURDAKAN1, Ülkü BAYAR2, Şükrü Oğuz ÖZDAMAR1
1Departments of Pathology, Karaelmas University, Faculty of Medicine, ZONGULDAK, TURKEY
2Departments of Gynaecology and Obstetrics, Karaelmas University, Faculty of Medicine, ZONGULDAK, TURKEY
Keywords: Ectopic pregnancy, Ovary, Endometrioma
Heterotopic pregnancy is a very uncommon entity with a difficult
preoperative diagnosis. In the present study, we presented an ovarian
heterotopic pregnancy case, clinically mimicking endometrioma
developed in a 33-year-old female following an in vitro fertilization
procedure. The importance of clinical, histopathological, and
immunohistochemical examinations in the diagnosis of heterotopic
pregnancy are emphasized.
Ectopic pregnancy is defined as the implantation of an
embryo in a tissue other than the fundus or lower uterine
segment of the endometrium. Simultaneous intra- and
extrauterine (ectopic) implantation is referred to as a
“heterotopic” or “combined” pregnancy. Generally, the
ectopic site in a heterotopic pregnancy is the Fallopian
tube. Ovarian heterotopic pregnancy is a rare condition,
presenting significant diagnostic difficulties1-5
A 33-year-old pregnant woman who had undergone in
vitro fertilization (IVF) was admitted to our out-patient
obstetrics clinic complaining of vaginal bleeding during
fifth gestational week. She had previously been diagnosed
as mild endometriosis via laparoscopy, and had been
treated with conventional ovulation induction methods
for six months. At the time of admission, mild ovarian
hyperstimulation syndrome was detected by laboratory and
ultrasonographic examinations. The patient was followed up
at monthly intervals. She was hospitalized during the 31st
gestational week because of placenta previa and a caesarean section was subsequently performed during the 36th week.
Intraoperative determination of a hemorrhagic mass in the
left ovary and a pre-diagnosis of endometrioma necessitated
wedge resection. Microscopic examination revealed
chorionic villous-like structures within the hematoma, along
with a few isolated trophoblast-like cells and membranous
structures (Figure 1A−D
). Immunohistochemical analysis
showed positive reactions for pan-keratin, human placental
lactogen (hPL), and human chorionic gonadotropin (hCG)
in the trophoblast-like cells surrounding these villous
structures (Figure 2A−D
). In light of the histopathological
and immunohistochemical results, the case was diagnosed
as an ovarian heterotopic pregnancy. The female infant
delivered via caesarean section had a birth weight of
2700 g and an Apgar score of 2/7 and was placed under
intensive care in newborn unit. The patient exhibited no
complications after the operation and was discharged in
good condition on the third postoperative day.
Click Here to Zoom
|Figure 1: Degenerated chorionic villi and fetal membranes in the hematoma neighbouring the ovarian stroma
(H&E; A: ×40; B: ×100; C, D: ×200).
Click Here to Zoom
|Figure 2: A,B Human chorionic gonadotropin (hCG) and C,D human placental lactogen (hPL) immunoreactivity in trophoblastic
cells. (A,B: x200, C: x100, D: x400).
Heterotopic pregnancy, an uncommon condition, is
the occurrence of concurrent intrauterine and ectopic implantation. The risk of heterotopic pregnancy in
spontaneous pregnancies is quite low. However, the
increasing frequency of assisted reproductive technologies
has increased the incidence of such cases1-8
. In the
present case, an ovarian heterotopic pregnancy developed
in a 33-year-old female who received IVF treatment due to
primary infertility. Our case is consistent with the view that
heterotopic pregnancy risk is elevated in cases involving
assisted reproductive technologies.
The most common site of implantation in heterotopic and
ectopic pregnancies is the Fallopian tube. Although less
common, implantation may also occur in the tubal fimbriae,
abdominal cavity, uterine interstitium, and uterine cornua.
However, ovarian heterotopic pregnancies are quite rare1-9.
Ovarian heterotopic pregnancy may be clinically and
radiologically confused with tubal ectopic pregnancy, hemorrhagic corpus luteum cysts, or endometriotic cysts.
Ectopic pregnancy should be considered in patients who
present with pelvic pain and have risk factors, regardless
of whether they have menstrual irregularities. Serum beta
hCG levels and a careful radiologic study are important
for diagnosis3,5,9. Macroscopically, ovarian heterotopic
pregnancy appears as a space-occupying hemorrhagic mass
in the ovary with a blue−purple color. During surgery,
approximately two-thirds of these cases are confused with
hemorrhagic corpus luteum3-6.
In the present case, no symptoms or clinical signs suggestive
of ovarian heterotopic pregnancy was detected during
routine prenatal check-ups. During the caesarean section
performed during the 36th week of the pregnancy due
to placenta previa, the discovery of a hemorrhagic mass
in the left ovary and a pre-diagnosis of endometrioma
prompted the surgeons to perform a wedge resectomy. The histomorphological features of placental tissue from the
ectopic fetus were consistent with a pregnancy in its first
trimester. Placental tissues appeared to be surrounded by
inflammatory cells and fibrous tissue in the hematoma. The
remnants of the chorionic villi were fibrotic and degenerated,
and very few trophoblastic cells were observed. These
findings indicate that the ovarian heterotopic pregnancy
had ended in the first trimester, which is consistent with
the literature, along with involution of the placental tissue.
Ovarian heterotopic pregnancies typically exhibit an
asymptomatic course due to ending of the pregnancy at an
early stage and involution of the placental tissue.
The clinical diagnosis of heterotopic pregnancy
should be supported by a histopathological diagnosis.
Histopathological examination reveals chorionic villouslike
structures, trophoblastic cells, and/or membranes
within the hematoma. Some ectopic pregnancies may form a chronic inflammatory mass, with trophoblastic tissue
involution. This condition is known as a ‘chronic ectopic
pregnancy,' and many samples are required to detect the
few degenerated villi. Demonstrating trophoblastic cells by
immunohistochemical techniques contributes significantly
In the present case, the histomorphological appearance
was confused with an organised hematoma, due to
placental tissue that had undergone involution. However,
the immunohistochemical determination of keratin, hPL,
hCG, and a few trophoblastic cells verified the diagnosis of
ovarian heterotopic pregnancy.
Treatment of these cases is complicated by the coexisting
intrauterine pregnancy. Removal of the gestational sac
by laparoscopy or laparotomy is the treatment of choice.
However, selective embryo reduction by direct injection of potassium chloride or hyperosmolar glucose into the
ectopic gestational sac is another treatment option9-13.
In conclusion, ovarian ectopic (or heterotopic) pregnancy
should be considered in the differential diagnosis of
hemorrhagic ovarian masses, particularly in pregnancies
resulting from assisted reproductive technologies. In such
cases, establishing a preoperative diagnosis is very difficult.
A detailed histopathological examination and the use
of immunohistochemical techniques provide important
information during differential diagnosis.
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