Hysteroscopic management of intramural ectopic pregnancy

Discussion

The aetiology and pathophysiology of intramural ectopic pregnancy are still unclear due to limited data in the literature. However, three questions emerge when trying to explain this rare phenomenon; how the conceptus gained access to the myometrium, how it reached there and how it got implanted. For a conceptus to implant within the myometrium, we believe that three contributing factors have to exist together to facilitate the occurrence of intramural ectopic pregnancy. First and most commonly reported risk factor is the presence of a false tract communicating the endometrium with the myometrium, which usually results from the previous uterine trauma during instrumentation, for example, dilatation and curettage, hysteroscopy or, as a result of, uterine surgery, for example, caesarean delivery, myomectomy.6 The second risk factor facilitating this condition is IVF-ET, in which embryos will be conveyed erroneously through the previously created false tract to be sited within the myometrium, rather than the normal uterine cavity.6 In the case presented, conducting ET without ultrasound guidance may have facilitated this. The third important risk factor is the presence of adenomyosis, which increases the receptivity of the myometrium and may explain implantation in the myometrium. According to Lu et al,4 adenomyosis seems to be the most reasonable factor in the development of intramural pregnancy.4 This is due to the fact that deep adenomyosis has enough endometrial tissue to respond to oestrogen and progesterone and demonstrate decidualisation, which could be a potential site for blastocyst implantation.4 7

Previous case reports have pointed to either one or more of the above-mentioned risk factors. May be partly because hysteroscopy was not done in some of these cases, so we would never be able to tell whether there was a false tract and partly because the diagnosis of adenomyosis can be easily overlooked especially in the context of a gravid uterus. Our case provides some understanding of the aetiology of intramural pregnancy by documenting the coexistence of all predisposing factors (false passage created by previous procedure, adenomyosis and IVF -ET).

On the other hand and paradoxically, few cases have been reported in the literature without any predisposing factors.8 9 Increased lytic activity of syncytiotrophoblast and defective decidualisation that allow the conceptus to penetrate into the myometrium in a way similar to placenta accreta may explain such cases in which there are no obvious predisposing factors.2 10

Pelvic pain and uterine bleeding in the presence of a positive pregnancy test are the hallmarks of an ectopic pregnancy. However, patients may remain asymptomatic till uterine perforation and massive haemorrhage develop, which might require hysterectomy, resulting in subsequent loss of fertility.1 Thus, a prompt and accurate diagnosis is crucial to avoid such complication.

TVUS is usually the first-line diagnostic tool and typically shows a gestational sac completely surrounded by myometrium with a ‘ring of fire’ appearance on Colour Doppler examination. Three-dimensional TVUS is more advantageous as it allows a more accurate diagnosis of the location of the gestational sac within the myometrium by multiple scan planes and provides better visualisation of the endometrium and myometrium separately.11

MRI can be of value as it confirms the ectopic location of the gestational sac and provides better visualisation of the myometrium and endometrium separately. However, although it has been considered by some researchers as the gold standard for diagnosis of intramural pregnancy,3 12, Memtsa et al concluded that diagnosis can be established in most cases with experienced ultrasound operators without the need for additional imaging.3 Diagnostic hysteroscopy, although its use in cases with intramural ectopic pregnancy, has not been consistently reported in the literature, is a very valuable tool, as it allows direct visualisation of the uterine cavity and tubal ostium, confirming the absence of the conceptus in the uterine cavity and also as, in our case, it had another value in identifying the false tract and visualising the conceptus within its upper part.

The prognosis of the pregnancy is very poor as it rarely advances to the second trimester with a high risk of uterine rupture and haemodynamic instability. Only one case in the literature has been reported when gestation continued without rupture for 30 weeks, resulting in neonatal survival after caesarean hysterectomy.13

Early diagnosis, when the patient is haemodynamically stable, allows the consideration of different treatment options. Treatment modalities reported in the literature for intramural ectopic pregnancy from the least to the most invasive include expectant management, medical management (using systemic administration of methotrexate or local administration of methotrexate or potassium chloride), uterine artery embolisation (UAE), surgical enucleation and hysterectomy.8 Although hysteroscopy has been reported in the management of caesarean scar ectopic,14 we could not find any report for its use in the management of intramural ectopic pregnancy.

Expectant management was occasionally reported;2 however, the most commonly used management is the medical approach. This may be achieved by local administration of methotrexate or potassium chloride or the systemic administration of methotrexate, using a single or multiple-dose regimen.15 However, this requires close follow-up, may require repeating the dose, may fail, besides the side effects of the use of methotrexate as well as the need to postpone future pregnancy for some time because of teratogenicity.

UAE may have a role by itself or before surgical management to decrease bleeding.16 However, this modality requires a multidisciplinary approach and, thus, may take time to arrange and to schedule the patient for the procedure, causing further delay with increased risk for uterine rupture, as reported by Fadhlaou et al 17.17

Conservative surgical management aims to remove the ectopic pregnancy with preservation of the uterus. This can be achieved with enucleation or wedge resection of the intramural ectopic pregnancy with myometrial reconstruction, which can be done via laparotomy18 or laparoscopy.19 Park et al described laparoscopic incision, aspiration and interrupted sutures.20 Such modality may be suitable when the ectopic pregnancy bulges through the serosal surface, which occurs in a more advanced gestation. It has the drawbacks of increased morbidity of surgical management. It also requires reconstruction of the myometrium, which can represent a risk of rupture in future pregnancies.

In the current case report, we used operative hysteroscopy for the management of intramural ectopic pregnancy. Up to the best of our knowledge, this is the first case report of intramural ectopic pregnancy to be managed with hysteroscopy in the literature. The presence of false tract created by previous uterine instrumentation facilitated the use of hysteroscopy for management. In this case, we used the resectoscope loop to mechanically remove the products of the conception without the utilisation of electric energy, which should be handled carefully as there is a higher risk of uterine perforation due to thinning of the myometrium remaining behind the conceptus. We consider this approach as the least invasive approach, allowing removal of retained products of conception under vision achieving immediate cure of the condition, without the need for reconstruction of the myometrium and the morbidity associated with other approaches. The possible complications of hysteroscopy in these cases can include increased risk of uterine perforation (which may require laparoscopy/laparotomy for the repair of the defect) as well as the risk of bleeding, which can be controlled by electrocoagulation but if uncontrollable may rarely require hysterectomy.