Spontaneous ectopic pregnancy occurring in the remnant tube after ipsilateral salpingectomy: a report of 2 cases

Abstract

Ectopic pregnancy occurring in the remnant tube after ipsilateral salpingectomy is assumed to be rare. We report 2 cases of spontaneous ectopic pregnancy occurring in the remnant tube that were treated surgically. Even in spontaneous pregnancy, attention should be paid to the remnant tube so as not to miss an ectopic pregnancy after previous salpingectomy.

Introduction

Ectopic pregnancy is a major gynecologic emergency occurring in 1% to 2% of all pregnancies [1, 2]. The incidence of ectopic pregnancy has increased over recent decades, which is partly due to the increased prevalence of sexually transmitted infections and the use of assisted reproductive technique (ART). However, ectopic pregnancy in the remnant tube after ipsilateral salpingectomy is rare and usually associated with reproductive techniques, being less likely to occur after natural conception. In the present paper, we report 2 cases of spontaneous ectopic pregnancy occurring in the remnant tube after previous ipsilateral salpingectomy.

Case reports

Case 1

A 34‐year‐old gravid 0, para 0 woman with infertility had been in follow‐up for 2 years. Right salpingectomy was performed because of a right hydrosalpinx 5 months before. She conceived spontaneously but no intrauterine gestational sac was visible through transvaginal ultrasonography. She was referred to our outpatient clinic at 47 days of gestation under suspicion of ectopic pregnancy. On investigation, her urine human chorionic gonadotropin (hCG) level was 7,084 IU/L, screening for Chlamydia was negative. A transvaginal scan revealed an empty uterus and a right adnexal mass measuring 3 × 2 cm, consistent with a right ectopic pregnancy. Emergency laparoscopy was performed to confirm the diagnosis.

Intraoperatively, there was minimal bleeding in the pouch of Douglas and a right cornual ectopic pregnancy was detected. The distal end of the remnant tube was closed and the left tube was normal. There was adhesion between the tubal stump and the right ovary. Pregnant corpus luteum was noted in the left ovary. The pregnant cornual portion was carefully excised using the harmonic scalpel, and histopathological examination confirmed the presence of chorionic villous tissue inside the lumen of the fallopian tube.

Case 2

A 35‐year‐old gravid 7, para 3 woman underwent laparoscopic left salpingectomy for tubal pregnancy at the age of 34. She conceived spontaneously and presented at 48 days of gestation. A transvaginal scan showed no evidence of intrauterine pregnancy but a left adnexal mass measuring 2.5 cm was present. Her urine hCG level was 1,090 IU/L. Diagnostic laparoscopy was performed based on the ultrasound finding of an empty uterus and previous history of ectopic pregnancy. Laparoscopy revealed an ectopic pregnancy in the isthmic portion of the left remnant tube (Fig. 1). The uterus was normal in axis and mobile. We could not find out the adhesion in her pelvic cavity. The distal end of the remnant tube was closed. Pregnant corpus luteum was noted in the right ovary. The unruptured portion was removed using the harmonic scalpel, and the specimen confirmed the diagnosis of left tubal ectopic pregnancy.

Figure 1.

Isthmic pregnancy in the remnant tube (arrow) during laparoscopic surgery

Discussion

Exact incidence of ectopic pregnancy occurring in the remnant tube after ipsilateral salpingectomy is not known; however, Takeda reported an incidence of 1.16% in their department [3]. Thus, spontaneous ectopic pregnancy after ipsilateral salpingectomy is an unusual occurrence [4].

Several possible mechanisms have been described for a recurrent ipsilateral ectopic pregnancy after previous salpingectomy. One theory explains that spermatozoa pass through the patent tube into the pouch of Douglas, then travel to fertilize the ovum on the side of the diseased tube. The fertilized ovum then implants on the stump of previous ectopic site. A second theory suggests transperitoneal passage of the fertilized egg through the contralateral intact uterine tube. A third theory says despite ligation, lumina remain intact in the interstitial portion and distal remnant of the fallopian tube. This allows communication between the endometrial and peritoneal cavities and thus migration of the fertilized ovum or spermatozoa from the endometrial cavity to the distal remnant of fallopian tube [5, 6]. In our cases, because the distal end of the remnant tube was closed and the corpus luteum was in the ovary on the opposite side of the ectopic tube, it is conceivable that after ovulation from the contralateral ovary, an oocyte may have been normally fertilized in the tube and later taken up to the remnant tube by intrauterine transmigration [3].

Because of its rarity, the possibility to prevent this type of ectopic pregnancy is unknown. Therefore, to decrease the risk of recurrence, care should be taken not to leave a long stump when performing salpingectomy for ectopic pregnancy. Spontaneous occurrence of interstitial/cornual pregnancy after ipsilateral salpingectomy has been reported [7]. Thus, even if nearly complete resection of the tube is achieved, avoiding occurrence of ectopic pregnancy in the remnant portion of the tube after ipsilateral salpingectomy/adenectomy may be difficult.

In our cases, isthmic portion and interstitial ectopic pregnancies in the remnant tube occurred after ipsilateral salpingectomy. Interstitial pregnancy is a rare entity of ectopic pregnancy, accounting for 2% to 4% of all tubal pregnancies. These ectopic pregnancy locations are associated with increased risk of rupture and severe bleeding at an early gestational age, because of the decreased ability of distention of the interstitial part of the uterine tube and increased vascularity of this area. While the overall mortality rates for ectopic pregnancies over the past five decades have steadily decreased to 0.14%, the case mortality rate for interstitial pregnancies remains at 2.0% to 2.5% [8]. Tulandi reported that ipsilateral salpingectomy, previous ectopic pregnancy, and in vitro fertilization are predisposing factors for interstitial pregnancy [9]. In fact, whether or not ART is scheduled, the chances of an embryo spontaneously implanting at the cornu or at the residual tubal stump are probably higher in such cases. We stress that whenever there is a history of prior salpingectomy and at least 1 normal functioning ovary remains, careful ultrasound monitoring should be provided from the early stages.