G3p2 (2002)

[Amabella Batton]

Corresponding Author : Glaiza S. de Guzman

Department of Obstetrics and Gynecology, Universityof the Philippines, Philippine General Hospital, TaftAvenue, Manila, Philippines.

Email: [email protected]

Ovarian pregnancy is a rare variant of ectopic pregnancy, accounting for 0.5 to 3% of all extrauterine pregnancies [1]. Evenwith the advent of accessible and reliable diagnostic methods,accurate assessment is often difficult. Patients typically presentwith nonspecific symptoms including abdominal pain and vaginalbleeding. Devastating sequelae include hemodynamic compromise from rupture and hemorrhage. Early and accurate diagnosiswith imaging modalities is vital due to the high maternal and neonatal mortality rates. However, the diagnosis is more often madeintraoperatively [1,2].

A 37-year-old G3P2 (2002) consulted at the emergency roomof a tertiary training hospital with findings of intrauterine fetaldemise on sonography. She has no previous surgeries, history ofsexually transmitted infections, contraceptive use, or use of assisted reproductive technology. The fetus was palpated to be inbreech presentation with an estimated fetal weight of 1200 to1400 grams. On internal examination, her cervix was closed, uneffaced, posterior, and firm. Transvaginal ultrasound showed asingle fetus in breech presentation with no cardiac and somaticactivities at the cul-de-sac, posterior to a normal empty uterus(Figure 1). There was overlapping of cranial sutures and exaggerated spinal curvature. Sonographic impression was an abdominalpregnancy, single fetal demise at 28 1/7 weeks age of gestation byfemoral length. The sonographic estimated fetal weight was 1044grams by Hadlock.

An abdominopelvic computed tomography (CT) scan showed alarge, globular abdominal mass measuring 16.7 x 13.6 x 13.9 cm,likely representing a gestational sac with internal fetal structures(Figure 2). It was intimately related to the posterior aspect of theuterine isthmus. A heterogeneously enhancing curvilinear focus,likely representing the placenta is noted in its right superoanterioraspect. Feeding vessels were seen arising from a branch of theright internal iliac artery.

Preoperative embolization of the feeding vessels was doneunder total intravenous anesthesia. An abdominal aortogrammapped the feeding vessels of the placenta. Angiograms showedits arterial supply from tiny and tortuous branches of a parasiticartery arising from the right internal iliac artery. No other arterial supply from the branches of the abdominal aorta was noted.Using Progreat microcatheter, polyvinyl alcohol particles were injected into the feeding artery until complete cessation of flow wasachieved.

Exploratory laparotomy was done the following day. Intraoperatively, there was no hemoperitoneum. No normal right ovary wasvisualized.Occupying its place was an irregular cystic mass with intact capsule measuring 23.0 x 16.5 x14.5 cm with a demised fetusinside (Figure 3). There were dense adhesions to the cul-de-sacand right pelvic sidewall. Inadvertent rupture of the capsule wasincurred during adhesiolysis. From the point of rupture, the fetalparts were visualized. Cut section of the cystic mass revealed ameconium-stained stillborn baby girl weighing 1410 grams (Figure4). The left adnexa and the uterus were grossly normal.

The patient tolerated the procedure well with minimal bloodloss. She had an unremarkable postoperative course and was discharged well on the second postoperative day. Histopathology result is consistent with an ovarian pregnancy at the right ovary.

The ovaries are rare sites for ectopic implantation. Ovarianpregnancy frequently poses diagnostic dilemma for obstetriciansdue to its varied and nonspecific clinical presentation.The varioushypotheses postulated to explain implantation anomalies causing ovarian pregnancy include ovum liberation delay, tunica albuginea thickening, and tubal dysfunction [4]. These hypothesesare due to an increased risk of ovarian pregnancy in patients withpelvic inflammatory disease. The inflammation causes thickeningof the tunica albuginea which will eventually delay the liberationof ovum. Tubal dysfunction likewise increases the risk of ovarianpregnancy. The use of an intrauterine device was disproportionately associated with ovarian pregnancy [2]. Other risk factorsreported are endometriosis, sexually transmitted diseases, ovulation induction agents, tubal sterilization and a history of abdominal surgery [1]. Despite not having the documented risk factors,the patient still developed ovarian pregnancy.

Common complaints include abdominal pain and vaginalbleeding, similar to tubal pregnancies. The mean age of gestationof ovarian pregnancies reported in literature is 45 days [5]. Rupture usually occurs before the end of the first trimester and mayoften present with hemodynamic instability. Most cases (91.0%)present with rupture during the first trimester, with 5.3% and3.7% occurring during the second third trimesters respectively[6]. In our case, the ovarian pregnancy continued up to the thirdtrimester without ovarian rupture.

Diagnosis is difficult since it mimics other forms of ectopicpregnancies as in our case. In earlier age of gestation, sonologicfindings may mimic those of tubal pregnancies, ruptured corpusluteum, or adnexal masses in the absence of a yolk sac or fetalheart motion [1]. In a case series by Comstock et al., [7] an ovarian pregnancy is seen sonologically as a wide echogenic ring withan internal echolucent area compared to a thin tubal ring of tubalpregnancies or a corpus luteum cyst [7]. The use of 3D ultrasoundhas been reported to improve early detection. However, whenpresented with an advanced pregnancy, imaging studies may attimes be difficult to interpret. In our patient, the first ultrasoundshowed an intrauterine pregnancy. The diagnosis of an ectopicpregnancy may have been missed if focus was only on biometry ofthe fetus. Sonographic diagnostic accuracy is operator-dependentand careful examination of pregnancy locations must be undertaken to avoid catastrophic events such as rupture, hemorrhage,and cardiovascular compromise [3,4].

The classic management option for ovarian pregnancies is surgical in the forms of wedge resection, cystectomy, or oophorectomy either through laparoscopy or laparotomy [4]. Medicalmanagement has also been described in literature for cases ofunruptured ovarian pregnancies [2,4]. Etoposide and methotrexate have been used for persistence of trophoblastic tissues [8].Decision making becomes more difficult when the diagnosis ismade at an advanced age of gestation. As pregnancy progresses,vascular supply through feeding vessels to the ectopic gestationbecome abundant. This may necessitate devascularization techniques or preoperative embolization as in this case.

Locating the sites of ectopic pregnancies remains a diagnostic challenge. Despite benefits of imaging procedures, definitivediagnosis can only be made during surgery [1,6]. Careful preoperative planning should be undertaken. In our case, embolizationwas done preoperatively to map the vascular supply of the ectopic gestation and to minimize risk of bleeding from its feedingvessels. Minimal blood loss was incurred during the operation.

While recent advances in biochemical testing and sonology hasallowed for the earlier detection and diagnosis of ectopic pregnancies, diagnosis of ovarian pregnancy remains to be problematic. Diagnostic imaging accuracy is imperative in the recognition ofthis entity. High index of suspicion, early recognition and promptintervention are needed to avoid both maternal and fetal compromise in cases of viable gestation.

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