Angular vs. interstitial pregnancy: A case report highlighting diagnostic nuances with stark management differences

Abstract

Background: In the literature, the terms “angular”, “interstitial” and “cornual” have often been inappropriately interchanged. The consequence is under-recognition of their differences as well as inaccurate imaging guidelines which do not reliably distinguish them as distinct entities. Angular pregnancies should be considered viable and may be managed to term. Case: A woman at 7w5d was transferred for surgical management of a presumed interstitial ectopic pregnancy. Sonography and MRI confirmed an eccentric fundal pregnancy with a thin myometrial mantle of 2–5 mm; the diagnosis of interstitial pregnancy was favored. Upon laparoscopy, the round ligament was displaced lateral to the pregnancy bulge and the diagnosis of angular pregnancy was thus apparent. The pregnancy was continued to term and delivered via repeat cesarean section without incident. Conclusion: Angular and interstitial pregnancies are different entities which cannot always be reliably distinguished via imaging alone. Diagnostic laparoscopy may be a final step in determining pregnancy location. Angular pregnancies should be considered potentially viable and may be managed to term. Keywords: Angular pregnancy, Cornual pregnancy, Ectopic pregnancy, Interstitial pregnancy, Obstetric ultrasound, Diagnostic laparoscopy, Eccentric pregnancy