Discussion
In this case report, we presented the challenging diagnosis and management of a cornual ectopic pregnancy case. Cornual pregnancy is rare, accounting for approximately 2-4% of all ectopic pregnancies [1]. By definition, it refers to the implantation and development of a gestational sac at the proximal and lateral regions of the uterus (aka uterine horns or cornua). As with the majority of other types of ectopic pregnancy, cornual pregnancy diagnosis is based on β-hCG measurments and transvaginal ultrasound findings [2]. Ectopic pregnancy mortality rate has been documented to be as high as 9-14%, rendering it the leading cause of maternal death in the first trimester of gestation [3], while cornual pregnancy In particular may lead to uterine rupture in up to 48.6% of women within the 6th to 26th week of gestation [6]. Given the aforementioned risk, accurate, timely diagnosis and effective treatment are paramount for the safety of the pregnant woman and in ensuring that she will be able to conceive and gestate again in the future.
In the present case report, while clinical evidence was indicative of ectopic pregnancy, the precise locus could not be located ultrasongraphically. Therefore, MRI scanning was employed as an alternative, which did manage to verify the diagnosis. Kao et al [7] in their review describe that cornual pregnancy may be diagnosed via MRI when the gestational sac is identified at the uterine cornu and is surrounded by of an uninterrupted junctional zone that separates it from the endometrium. They additionally stress the need for radiologist to be adequately prepared to diagnose ectopic pregnancy, as ultrasonographic assessment may not always suffice [7], similar to our experience during the management of the present case.
Given the increased risk of adverse maternal outcomes, immediate and effective management of cornual pregnancy is paramount. Conservative, pharmacological management with methotrexate administration has been tested as a non-invasive option for the treatment of cornual pregnancy, via local or systemic methotrexate [8]. The first reported case of successful resolution of ectopic pregnancy using this methodology was by Tanaka et al [9]. Since then, multiple similarly successful cases have been published [10]. Larger case series have also indicated the efficacy of this approach, with Jermy et al [11] applying this methotrexate regimen option during the management of 20 cases of ectopic interstitial/cornual pregnancies. They reported successful pregnancy resolution in 94% of cases, they do stress however that this method should be reserved for cases with lower levels of β-hCG [11]. Cassik et al [12] in their study of 42 women with ectopic interstitial/cornual pregnancy concluded that low levels of initial β-hCG were the only statistically significant predictor of a final positive outcome, with mean β-hCG levels in the successful group being 3216 mIU/ml. These conclusions are also corroborated by the latest version of the Royal College of Obstetrician and Gynaecologists guidelines on the matter [8]. In our case, β-hCG levels were increasing beyond the levels where conservative management and monitoring would be a safe option; therefore, a more invasive approach was preferred.
The traditional, well-established, safe approach to cornual ectopic pregnancy is cornual resection via laparotomy or laparoscopy, while hysterectomy may be reserved as a last resort option in life-threatening cases [13,14]. Two primary methodologies have been proposed, namely cornuotomy and corneal resection with salpingectomy, both being reported as comparable, with regard to surgical complications and future fertility outcomes [15]. Regardless of the applied technique, adverse effects on future fertility potential, as well as increased risk of uterine rupture in future pregnancies still remain prevalent risks associated with these methodologies [4,16]. In a study by Lee et al [17], the investigator compared the two approaches and concluded that there were no statistically significant differences between the two approaches apart from operative time (77.11 ± 23.97 min for cornual resection versus 59.36 ± 19.32 min for cornuotomy, p=0.03). No other surgical parameters demonstrated statistically significant differences between the two methods, including no differences in the rate of persistent interstitial pregnancy following treatment [17]. In our case, since detailed imaging data regarding the sac’s location were available and considering the patient’s wish to maintain her fertility potential for future attempts, a less radical option was preferred instead.
Hysteroscopic resection of cornual pregnancy is a minimally invasive alternative approach that allows for direct visualization and removal of all the products of gestation, without affecting the rest of the uterus. The first such hysteroscopic resection was reported by Meyer et al [18], performed under laparoscopic guidance. Sanz et al [19] further expanded on the concept via hysteroscopy under ultrasonographic guidance and Pal et al [5] combined laparoscopic and ultrasonographic guidance to optimize their hysteroscopy. More recent reports of successful hysteroscopic resection of pregnancy, following failed initial methotrexate treatment, are indicative of the potential of this technique as an alternative with reduced impact on future fertility and maternal outcomes [20,21]. In our case hysteroscopy was performed without prior methotrexate administration, since MRI data were available and indicated that the products of gestations could be safely removed without the need for laparoscopic intervention.
To our knowledge, this is the first reported case where a combination of transvaginal ultrasound and MRI findings guided the successful hysteroscopic removal of a cornual pregnancy, with the use of a simple resectoscope, without any complications. Given the constant increase in infertility rates, a method that allows for subsequent attempts at conception and pregnancy, without affecting the fertility potential or increasing the risk for uterine rupture during future attempts; such as hysteroscopic resection, seems a promising option. Future research should examine this alternative with larger multi-center studies and patient series.