2 Discussions

The interstitial portion of the fallopian tube corresponds to the proximal segment incorporated into the uterine muscle wall (0.7×1.5 cm). A pregnancy implanted at this site is called an interstitial pregnancy (Tulandi, 2013). When it is located in a rudimentary horn of a bicorne uterus or in the remaining stump of a trunk treated with salpingectomy, it is called corneal pregnancy. Interstitial pregnancy is located outside the round ligament as opposed to the angular pregnancy within (Bouyer et al., 2002). Ectopic pregnancies: interstitial, angular (developed in the tubal ostium at the bottom of the uterine cavity) and cornual localization is often grouped together and represent the same clinical and therapeutic entity (Bouyer et al., 2002).

The macroscopic examination of our hysterectomy part confirms well the interstitial seat of the pregnancy (Figures).

The incidence of interstitial pregnancies is between 2-3% of all ectopic pregnancies and allows relatively late development until 16 weeks of amenorrhea (11 weeks of amenorrhea for our case). Interstitial pregnancies are particularly hemorrhagic due to a rich corneal vascularization and greater myometrial distension, so that the rate of mortality by interstitial pregnancy is logically 2 to 3 times that of tubal pregnancies (Malek-mellouli et al., 2012).

Risk factors are similar to other ectopic pregnancies (history of ectopic pregnancy, pathology and tubal surgery, intra-uterine dystylbene exposure, genital infections, tobacco, in vitro fertilization) except for ipsilateral salpingectomy which is a specific risk factor to interstitial pregnancy (Tulandi and Al-Jaroudi, 2004), in our patient alone contraception by micro progestative was found as risk factor for ectopic pregnancy.

The diagnosis is based on synthesis of clinical examination, plasma HCG and transvaginal ultrasound.

The ultrasound diagnosis of interstitial pregnancies is difficult, and these pregnancies are often symptomatic later, leading to delays in management until the second trimester, but ultrasound criteria have been proposed by Timor-Tritsch for this diagnosis: An empty uterine cavity, an eccentric gestational sac and located at>1 cm from the lateral wall of the uterine cavity and a thin (<5 mm) layer of myometrium around the sac (Timor-Tritsch et al., 1992). 3D ultrasound as well as MRI also allow early accurate diagnosis if interstitial pregnancy is suspected on 2D ultrasound (Filhastre et al., 2005; Júnior et al., 2007).

In our case the diagnosis was delayed to 11 weeks of amenorrhea, the patient did not consult since she attributed its disorders of the cycle to the contraceptive treatment, the ultrasound examination (Figures) confirmed the diagnosis of cornual pregnancy, there is no 3D probe in our department and it was not considered useful to perform an MRI since it was decided to perform a laparoscopy.

By the past, the treatment of interstitial pregnancy consisted of salpingectomy and corneal resection by laparotomy, probably as a result of delayed diagnosis (Moawad et al., 2010) currently interstitial pregnancy is typically diagnosed at an early gestational age and prior to rupture, leaving the opportunity for conservative medical or surgical treatment (Hussein et al., 2014). However, in the presence of signs of severity (hemodynamic failure and presence of abundant hemoperitoneum), the treatment should be surgical by laparoscopic route if possible, but most often by laparotomy. Conservative treatment of the uterus will be preferred whenever possible, but radical treatment (hysterectomy) may be necessary to control hemorrhage (Hussein et al., 2014). 

Methotrexate (MTX) is the cornerstone of medical management with different routes of injection (Misme et al., 2015): intramuscular, “in situ” with ultrasound or “in situ” by laparoscopy at a dose of 1 mg / kg. Other molecules are also used, alone or in combination with methotrexate: KCl in situ (5 mmol) (especially in heterotopic pregnancies or in case of contraindication or failure of treatment with methotrexate), mifepristone when Initial progesteroneemia is greater than 9 ng / mL (Rozenberg et al., 2003).

The most frequent regimen in the literature is the multi-dose regimen (MTX 1 mg / kg IV / IM on day 1, 3, 5 and 7 with Leucovorin 0.1 mg / kg oral on day 2, 4, 6 and 8 Re-administer therapy 7 days after the last dose) (Jermy et al., 2004) associated with surgical treatment in the event of deterioration of clinical condition. The success rate reported is 66% (Jermy et al., 2004). If, in the case of conventional tubal ectopic pregnancies, a single injection of MTX has become the standard, it appears that repeated interstitial doses are more interesting (Jermy et al., 2004; Moawad et al., 2010) for interstitial pregnancies. There is as yet no consensus on the protocol to be followed for the multidose regimen. There is no consensus regarding the limiting level of HCG or the presence of cardiac activity (Moawad et al., 2010).

Treatment by local injection of methotrexate by endovaginal route under ultrasound control, or especially by laparoscopic route, as well as injection supplements of IM methotrexate in addition to the in situ injection, appears to obtain better results compared to MTX by the general route (Jourdain et al., 2003; Jermy et al., 2004).

It is important to follow the decay of HCG until it is negated. The mean duration of undetectable HCG in serum is 43 +/- 64 days (Jourdain et al., 2003). An interstitial mass or heterogeneous area with persistent vascularization on ultrasound has been reported (Tang et al., 2006). Subject to negativity complete of HCG, they do not constitute a therapeutic failure (Tang et al., 2006).

In our team the management of interstitial pregnancy outside the context of rupture is a celioscopic injected injection of MTX associated on the same day with a single injection of MTX by IM (1 mg / kg), but concerning this patient; The size, the scalability of the pregnancy and the celioscopic observation of signs prelude to rupture, parinaminci, ecchymotic spots (Figures) should have directed us towards surgical treatment in first intention.

3 Conclusions

Interstitial pregnancy is a rare but dangerous localization of ectopic pregnancy, which should be considered during an intra-uterine localization eccentric to more than one centimeter of the lateral wall of the cavity, with a fine myometrial circumference. The reference treatment is laparoscopic surgery (in the absence of haemodynamic disorder). Medical treatment is more and more used; in the absence of a clear consensus, selection of patients must be discussed on a case-by-case basis to avoid a hazardous evolution.

Authors’ contributions

Ragmoun Houssem: Editing and supervision, read and approved the final manuscript; Daadoucha Abdrahmen: Participated in the drafting of the observation, read and approved the final manuscript; Benhlima Najeh: Participated in the drafting of the discussion, read and approved the final manuscript; Ajili Abir: Checking references. All authors read and approved the final manuscript.

Acknowledgments

We thank the anatomopathology department of Ibn El Jazzar Hospital, Kairouan.

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