Interstitial pregnancy: Diagnostic dilemma
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Authors
Mokashi , T
Das , S
Dutta , S
Issue Date
2021
Type
Scientific Paper
Language
Keywords
Research Subject Categories::VETERINARY MEDICINE::Obstetrics and gynaecology
Alternative Title
Abstract
345
Interstitial pregnancy – diagnostic dilemma
Mokashi, T; Das, S; Dutta, S
Luton and Dunstable Hospital, Luton, UK
Objective We present a series of 3 cases of Interstitial ectopic pregnancy (IP). All the 3 cases posed a diagnostic dilemma on the initial 2-D USS. Further imaging including 3-D USS proved effective in diagnosis and successful management of the patients.
Case reports: In our case series, 3-D transvaginal USS in coronal view, showing the connection of the endometrial cavity with the interstitial part of the tube, provided a conclusive diagnosis compared to 2–D ultrasound or MRI. The first patient presented at 7 weeks with abdominal pain and PV bleeding. The initial scan showed pregnancy of unknown location with cornual degenerating fibroid. BHCG on admission was 27 937 which prompted repeat USS which confirmed interstitial pregnancy. The second patient presented at 6 weeks with PV bleeding. Scan suggested complete molar pregnancy. BHCG was 48 402U/L. She underwent surgical management for the suspected molar pregnancy and products were sent for histology. The patient presented 1 week later with abdominal pain. Due to initial suspicion of molar pregnancy, bHCG was done (36 782 mU/L). Repeat transvaginal ultrasound scan showed right-sided interstitial ectopic pregnancy. Both cases were managed surgically with laparoscopic intramural instillation of diluted vasopressin around the base of the ectopic to minimize bleeding, followed by salpingotomy. In the third case, ultrasound-guided surgical evacuation of the uterus was performed, with an initial diagnosis of an angular intrauterine miscarriage. The women presented with recurrent irregular bleeding with a negative pregnancy test 5 weeks after the procedure. 2-D USS and MRI reported retained products with suspected arteriovenous malformation. 3-D imaging further confirmed a resolving interstitial pregnancy with increased myometrial vascularity, conservatively managed following MDT with cyclical hormones for 6 months, thus avoiding uterine artery embolization for one desirous of future fertility, with subsequent recovery from IP.
Discussion Ultrasound criteria for IP specify an empty uterine cavity with a gestational sac located laterally in the interstitial part of the tube, surrounded by less than 5 mm of myometrium in all imaging planes. The sonographic appearance of the ‘interstitial line sign’ in an IP has a sensitivity of 80% and specificity of 98%. In reality, the diagnosis can be challenging, posing a diagnostic dilemma with other differentials such as angular intrauterine pregnancy, fibroid with degenerative changes, or even molar changes with high beta HCG levels on 2-D imaging.
Conclusions Interstitial pregnancy can pose a diagnostic dilemma however with 3-D USS at the hand of expert desirable outcomes were achieved.
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Citation
Mokashi, T., Das, S., Dutta, S. (2021) Interstitial pregnancy: Diagnostic dilemma. BJOG: An International Journal of Obstetrics and Gynaecology. 128(Suppl 2): 24-25. DOI: https://doi.org/10.1111/1471-0528.3_16715