A Very Rare Case of Heterotopic Pregnancy in Natural Conception with Ectopic Pregnancy as Partial Mole!

Heterotopic pregnancy is defined as the coexistence of intrauterine and extrauterine gestation. It was first reported in 1708 as an autopsy finding. The incidence was originally estimated on theoretical basis to be 1 in 30,000 pregnancies. However, more recent data indicate that the rate is higher because of assisted reproduction and is approximately 1 in 7,000 overall and as high as 1 in 900 with ovulation induction. There might be an increased risk in patients with previous tubal surgeries. Heterotopic pregnancy can have various presentations. It should be considered more likely in the following cases: (a) after assisted reproduction techniques, (b) with persistent or rising chorionic gonadotropin levels after dilatation and curettage for an induced/spontaneous abortion, (c) when the uterine fundus is larger than for menstrual dates, (d) when more than one corpus luteum is present in a natural conception, and (e) when vaginal bleeding is absent in the presence of signs and symptoms of ectopic gestation. The treatment of a heterotopic pregnancy is laparoscopy/laparotomy for the tubal pregnancy.

This is a very rare case of heterotopic pregnancy in a 28-year-old female with 10 weeks of amenorrhea, with the ectopic pregnancy being a partial mole!!

Case Report

A 28-year-old female with 10 weeks of amenorrhea presented with USG report S/O live heterotopic pregnancy of 11.4 and 11.3 weeks, with ectopic pregnancy being partially ruptured with adjacent localized hematoma and hemoperitoneum. Emergency exploratory laparotomy with salpingectomy was performed, and intrauterine pregnancy was allowed to continue. The histopathological report revealed the ectopic pregnancy being partial mole. The patient is under regular follow up (Fig. 1).

Fig. 1.

Intra op: G sac with fetus at ampullary end of Rt sided fallopian tube

Discussion

A heterotopic gestation is difficult to diagnose clinically and is not as straightforward as the diagnosis of an ectopic pregnancy. Heterotopic pregnancy often goes unnoticed because of the presence of an intrauterine gestation sac. These patients usually present with lower abdominal pain in the first trimester. A relatively higher beta hCG levels for the period of gestation is a helpful diagnostic clue. Ultrasound examination, especially transvaginal sonography, has proven to be an invaluable tool in the diagnosis of this condition. The extrauterine pregnancy in cases of heterotopic pregnancy has a similar sonographic appearance as that of an isolated ectopic pregnancy. Majority of the reported heterotopic pregnancies are of singleton intrauterine pregnancies. Triplet and quadruplet heterotopic pregnancies have also been reported, though extremely rare (Fig. 2).

Fig. 2.

Microscopy: Avascular chronic villi with hydropic degeneration and trophoblastic proliferation. S/O partial mole

Although heterotopic pregnancy is more common with assisted reproductive techniques, it has been seen with natural conception as well [1]. The intrauterine gestation may undergo spontaneous abortion after surgery for ectopic gestation. However, there have been reported cases of heterotopic pregnancy in which post laparotomy/salpingectomy, the intrauterine pregnancy continued to full term delivering a healthy neonate.

Systemic methotrexate (MTX) or local injection of MTX cannot be used in a heterotopic pregnancy owing to its toxicity. In the case of a viable intrauterine pregnancy and methotrexate contraindication, injection of potassium chloride under transvaginal ultrasound or under a laparoscopy procedure appears to be the most adequate option. Patients with failure of medical treatment would require secondary surgery.

The treatment of a heterotopic pregnancy is selective surgical removal of the ectopic pregnancy through laparoscopy or laparotomy. The decision to allow the intrauterine pregnancy remains controversial. In this case, intrauterine pregnancy was allowed to continue. Histopathological report showed that ectopic pregnancy was partial mole.

A partial molar pregnancy results when one of two conditions happen: either two sperm fertilize one ovum or one sperm fertilizes the ovum but its chromosomes are accidentally duplicated [2]. In both instances, there is little chance of a viable embryo developing, though it is possible. Rare circumstances when a partial molar pregnancy results in a viable embryo or a molar twin pregnancy with one normal embryo happens, medical evidence suggests that the viable embryo will not survive. The mole will grow and spread, destroying the viable embryo.

In spite of extensive search for references, we were unable to find any references for a partial mole in heterotopic pregnancy and its management. However, this case secures a point of histopathological examination of every tissue removed as well as genetic and chromosomal testing for the viability and prognosis of intrauterine gestation.