Introduction

Ectopic pregnancy (EP) is an acute life-threatening obstetric emergency necessitating immediate diagnosis and management. EP accounts for 2% of all recorded pregnancies worldwide. ¹ The incidence is increased due to assisted reproductive techniques, sexually transmitted diseases, and delayed pregnancies. ^{2, 3} The commonest site is the fallopian tube, commonly known as the tubal ectopic.

An ectopic pregnancy that occurs within the remnant of the fallopian tube following the previous salpingectomy is called tubal stump pregnancy. Most of the reported cases of stump ectopic are preceded by artificial reproductive procedures. Such spontaneous pregnancy is a rare event, with an incidence of 1.16% of all EPs. Only a handful of cases have previously been described in the literature. ⁴

Case report:

A 26-year-old lady was referred to our hospital on 30th November 2020 with sudden onset, dull aching abdominal pain five days before admission. She was due for her menses on the day of admission. No history of vaginal bleeding. She had one cesarean delivery and one laparotomy for a right ovarian cyst. Details were not available.

At admission, she was resuscitated with fluids. She had tenderness in the lower abdomen. Shifting dullness was present. Pelvic examination revealed a normal-sized mobile uterus with fullness in the posterior fornix. Cervical motion tenderness was present. Her Urine pregnancy test was weakly positive. An emergency pelvic ultrasound revealed an empty uterine cavity with a homogeneous endometrial thickness of 12mm and a heterogeneous ill-defined mass posterior to the uterus of 10x6.5 cm suggestive of a clot, there was free fluid in the abdomen. The right ovary was not visualised. The left ovary was visualised. Findings were suggestive of ruptured ectopic. The side of the ectopic was not made out on ultrasound. On further investigation, serum ß-hCG level was 1265 mIU/ml, haemoglobin of 6.7gm/dl. Diagnosis of ruptured ectopic was made. Given the hemodynamic instability, an emergency laparotomy was done. Intra-operatively ruptured tubal stump ectopic with hemoperitoneum of 1800ml was found. The stump was clamped, cut, and ligated. The contralateral tube and ovary were grossly normal. She had an uneventful postoperative period and was discharged on the 5^th day.

Discussion

More than 90% of ectopic pregnancies occur in one of the fallopian tubes. Other sites include the cervix, ovary, cesarean section scar defect, and the abdominal cavity. ^{4, 5}

Tubal stump ectopic is an extremely rare variety of tubal ectopic pregnancy which is not yet classified. Most cases of stump ectopic are reported after artificial reproductive procedures. The occurrence of spontaneous stump ectopic is reported as a very infrequent type of ectopic. ⁶

The mechanism by which spontaneous stump ectopic pregnancies occur is hypothesized as follows:

• Despite surgical excision, the lumina remain intact or recanalize in the interstitial portion and remnant of the fallopian tube permitting communication between the endometrial and peritoneal cavities and hence the passage of the fertilized ovum or sperm from the uterine cavity to the remnant of the fallopian tube.

• Spermatozoa pass through the contralateral patent tube into the Pouch of Douglas, then journey to fertilize the ovum and implant on the side of the previous ectopic, within the tubal stump.

• Transperitoneal migration whereby the fertilized ovum on the side of the normal tube migrates and gets implanted on the tubal stump. ^{5, 6, 7}

The management is emergency resection of the remnant stump. Early diagnosis is important to prevent life-threatening haemorrhage leading to increased mortality.

Rupture of stump ectopic pregnancy has a higher mortality rate of 2.0 to 2.5% in contrast to other ectopic pregnancies where the mortality rate is 0.14%. ^{6, 7}

Conclusion

It is recommended that whenever salpingectomy is performed, excision close to the isthmic portion should be done without leaving a remnant of the tube. This is important as spontaneous recanalization can still occur even when the tubal stump is covered by the peritoneum.

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Conflict of Interest

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