Ectopic pregnancy represents a typical gynecological surgical emergency. Ovarian pregnancy is a particular entity due to its rarity, which is related both to its definition involving anatomical criteria and to well-defined diagnostic procedures. ¹ It occurs in approximately 1 in every 2,100 to 1 in 60,000 pregnancies, representing about 0.5% to 1% of all ectopic pregnancies. ² Unlike other forms of ectopic pregnancy, ovarian pregnancy remains a rare phenomenon independent of usual risk factors, with diagnosis often occurring during surgical intervention.

Patient X, a 40-year-old woman with blood group O positive, arrived at the emergency department experiencing acute pelvic pain, mild vaginal bleeding, and 8 weeks of amenorrhea. She is a G5P3A1 with a history of a tricicatricial uterus and a prior pregnancy that ceased developing at 7 weeks, which was subsequently curetted. She reported using condoms for contraception and had no history of contraceptive pill use. Upon admission, she exhibited pale conjunctivae, a blood pressure of 80/60 mmHg, and a pulse rate of 115 bpm. Examination revealed diffuse abdominal tenderness, especially in the left iliac fossa, along with dark, scant uterine bleeding and pain during uterine mobilization, particularly on the left side. The pelvic pain and vaginal bleeding had started one day prior to her visit. Transvaginal ultrasound indicated an empty uterus, a thin endometrium, and a heterogeneous mass in the left ovary measuring 2 × 3 cm, accompanied by a significant amount of fluid. Her beta-HCG level was positive at 3500 Miu/ml, hemoglobin at 10 g/dl, and prothrombin time at 80%. Due to the unstable hemodynamic state, an emergency laparotomy was performed for suspected ectopic pregnancy. Intraoperative exploration revealed a large volume of clotted blood (approximately 800 cc), a regular-sized uterus, and a mass in the left adnexa measuring about 10 × 9.5 cm, originating from the left ovary, with active bleeding from the mass ( Figure 1). A diagnosis of ruptured left ovarian ectopic pregnancy with active bleeding was made. Due to the uncontrollable bleeding from the left ovary and persistent hemorrhage, a left oophorectomy combined with a salpingectomy was performed ( Figure 2).

The postoperative recovery was uneventful, and histopathological examination confirmed the diagnosis of ovarian pregnancy, which the patient consented to treat surgically.

Ovarian pregnancy can be recognized using the pathological criteria established by Spiegelberg ³ which encompass the following: (1) the fallopian tube remains intact and is distinct from the affected ovary, (2) the gestational sac is situated in the typical location of the ovary, (3) the ovary housing the gestational sac is connected to the uterus via the ovarian ligament, and (4) ovarian tissue is present and integrated into the wall of the gestational sac.

Although ovarian pregnancy is a serious condition, its underlying mechanisms are not entirely clear but seems to be related to reflux of the fertilized ovum to the ovary. ⁴ Documented cases of ovarian pregnancies that occur after assisted reproductive technology support the reflux hypothesis. ⁵ Indeed, Implantation typically takes place at the site of the original follicular ostium, which is characterized by a high concentration of fibrin and newly formed blood vessels. This concept accounts for the intra-follicular and juxta-follicular variations of ovarian pregnancy. In rarer instances, implantation may occur away from the corpus luteum or even on the contralateral ovary, leading to juxta-cortical or interstitial forms, the mechanisms of which are still not well understood. Ovarian pregnancy may also be bilateral or part of a heterotopic pregnancy. ⁶

There are no established criteria for diagnosing ovarian pregnancy, and most of these pregnancies are discovered unexpectedly during surgical procedures. Typically, abdominal-pelvic pain precedes the diagnosis. These pains are associated with the rupture of the ovarian capsule due to the pregnancy, leading to hemoperitoneum. ⁴ Patients frequently present in emergency situations, often exhibiting substantial hemoperitoneum or even signs of hypovolemic shock. ¹ The accuracy of ovarian pregnancy diagnosis by imaging is not sufficiently documented to assess false negatives. ⁷ Multiple ultrasound findings have been documented in the literature. Certain ultrasound criteria are very suggestive of ovarian pregnancy localization: the presence of a round anechoic image with a hyper-echoic ring at the surface of the ovary, the presence of ovarian parenchyma such as a corpus luteum or follicle surrounding the mass, and a higher echogenicity of the mass compared to that of the ovary. ⁸ The contribution of Doppler to the diagnosis of ovarian pregnancy is uncertain; However, Atriv ⁹ identified that a resistive index below 0.39 demonstrated 100% specificity and 100% positive predictive value for ectopic pregnancy, although this index was noted in only 15% of ectopic cases (confidence interval 7% to 23%). He concluded that both low and high resistive indices could aid in differentiating ectopic pregnancies from corpus luteum cysts.

In some cases, ovarian pregnancy may lead to choriocarcinoma. ¹⁰

Unlike tubal ectopic pregnancies, tubal pathologies and surgeries do not seem to increase the risk of ovarian pregnancy. ¹¹ However, there is no consensus among experts regarding the role of pelvic inflammatory pathologies in the development of ovarian pregnancies. Additionally, the use of an intrauterine device (IUD) seems to be particularly associated with ovarian pregnancies. ¹² Recent literature indicates an increased incidence of ovarian pregnancy associated with infertility and assisted reproductive techniques. ¹³

The preferred treatment for ovarian pregnancy in women is laparoscopy and laparoscopic surgery. However, these procedures can become difficult if significant adnexal adhesions and hemodynamic instability obscure any hemorrhaging.

Several surgical techniques are possible, including enucleation of the ovarian pregnancy, cystectomy of the corpus luteum with trophoblast removal, curettage of the trophoblast with coagulation, or hemostatic suturing of the ovarian pregnancy bed with total ovarian preservation. ¹⁴ In other cases, due to advanced pregnancy development, oophorectomy or even annexectomy may be necessary. ¹⁵ This was the case for our patient. Regarding prognosis, ovarian pregnancy, due to the absence of tubal involvement, does not constitute a risk factor for subsequent ectopic pregnancies. ¹³

Ovarian pregnancy presents significant risks for patients and can lead to diagnostic confusion for practitioners due to its atypical symptoms. This case emphasizes the importance of thoroughly examining all potential ectopic pregnancy sites during transvaginal ultrasound, even with the slightest suspicion, prompt intervention is crucial for improving patient outcomes.

We have obtained written informed consent for publication from the patient.