Interstitial ectopic pregnancy | Radiology Reference Article | Radiopaedia.org
Interstitial ectopic pregnancy (also known as an intramural) is an important type of ectopic pregnancy with higher risks of rupture and haemorrhage compared to usual tubal ectopic pregnancies. On this page: Epidemiology Pathology Radiographic features Complications Treatment and prognosis Differential diagnosis Related Articles References Cases and Figures Epidemiology
It accounts for 2-4% of all ectopics (commonest site for an atypical ectopic pregnancy). The incidence is thought to be rising 7.Pathology
It occurs within the interstitial portion of the fallopian tube and therefore has the potential to grow to larger sizes than standard tubal ectopic pregnancies by the time of presentation.Risk factorsprior intrauterine instrumentationRadiographic featuresUltrasound
Sonographic features include: interstitial line sign 2an echogenic line from the mass to the endometrial echo complex, reportedly has high sensitivity (80%) and specificity (98%) may show an eccentric gestational sacthe diagnosis is suggested by visualisation of an intrauterine gestational sac or decidual reaction located high in the fundus, with 5 mm of surrounding myometrium in all planes ("myometrial mantle")
3D ultrasound may be helpful for delineating a gestational sac's location.MRIgestational sac is eccentric to the junctional zoneComplications uterine myometrial rupture: tends to occur by the 2nd trimester 5 greater tendency for massive haemorrhage (from above) Treatment and prognosis
The morbidity and mortality are higher (15x) due to later presentation and associated complications.
Management of an interstitial ectopic includes use of methotrexate (either systemic or local), potassium chloride (KCl) injection, conservative laparoscopic surgery, uterine artery embolisation, cornuectomy or hysterectomy. The latter two are usually reserved for emergency situations or in case of failure of the other methods.Differential diagnosis
For an eccentric gestational sac on imaging, consider: differential diagnosis of an eccentric gestational sac Related articles First trimester of pregnancy first trimester ultrasound findings in early pregnancy gestational sacmean sac diameter (MSD) yolk sac fetal polecrown rump length (CRL) confirming intrauterine gestation double decidual sac sign intradecidual sign double bleb sign pregnancy of unknown location (PUL) first trimester vaginal bleeding ectopic pregnancy pseudogestational sac decidual cast tubal ectopic ampullary isthmal fimbrial atypical ectopic pregnancies interstitial ectopic eccentric gestational sac interstitial line sign ovarian ectopic cervical ectopic scar ectopic abdominal ectopic live ectopic pregnancy heterotopic pregnancy tubal rupture failed early pregnancy pregnancy of uncertain viability (PUV) miscarriage threatened miscarriageirregular gestational sac missed miscarriage inevitable miscarriage incomplete miscarriage complete miscarriage anembryonic pregnancyanembryonic pregnancy in the exam yolk sac abnormalities irregular yolk sac calcified yolk sac echogenic yolk sac small yolk sac large yolk sac gestational trophoblastic disease subchorionic haemorrhage demise of a twin implantation bleeding aneuploidy testing antenatal screening nuchal translucency Ultrasound - obstetric ultrasound (introduction) obstetric ultrasound first trimester and early pregnancy gestational sac double decidual sac sign intradecidual sac sign mean sac diameter empty gestational sac pseudogestational sac yolk sac embryo/fetus crown rump length (CRL) fetal heart rate fetal tachycardia fetal bradycardia fetal bradyarrhythmia(s) physiologic gut herniation embryonic rhombencephalon amnion chorion Beta-hCG levels ectopic pregnancy tubal ectopic interstitial or cornual ectopic cervical ectopic ovarian ectopic abdominal ectopic heterotopic pregnancy Cesarean scar ectopic multiple gestations monochorionic monoamniotic twin pregnancy monochorionic diamniotic twin pregnancy dichorionic diamniotic twin pregnancy signs T sign twin peak sign subchorionic hematoma failed early pregnancy second trimester fetal biometry basic biometry biparietal diameter (BPD) head circumference (HC) abdominal circumference (AC) femur length (FL) amniotic fluid volume amniotic fluid index maximal vertical pocket method two diameter pocket method polyhydramnios oligohydramnios (mnemonic)oligohydramnios sequence fetal morphology assessment fetal echocardiography views four chamber view (fetal) LVOT view (fetal) RVOT view (fetal) nonvisualisation of the fetal stomach soft markers nuchal fold thickness ventriculomegaly absent nasal bonehypoplastic nasal bone choroid plexus cysts enlarged cisterna magna shortened fetal long bones shortened femur shortened humerus echogenic intracardiac focus (EIF) echogenic fetal bowel aberrant right sublavian artery fetal pyelectasis / fetal renal pelvic dilatation single umbilical artery sandal gap toes amnioreduction umbilical artery Doppler assessment single umbilical artery absent umbilical arterial end diastolic flow reversal of umbilical arterial end diastolic flow fetal middle cerebral arterial Doppler assessment fetal MCA pulsatility index (PI) fetal MCA peak systolic velocity (PSV) fetal MCA systolic/diastolic (S/D) ratio nuchal translucency chorionic villus sampling (CVS) and amniocentesis placenta low lying placenta placenta previa placenta accreta placenta increta placenta percreta placental abruption circumvallate placenta marginal cord insertion velamentous cord insertion vasa previa succenturiate placenta uteroplacental blood flow assessment placental tumours other gestational trophoblastic disease retained products of conception References 1. Callen PW. Ultrasonography in obstetrics and gynecology. W B Saunders Co. (2000) ISBN:0721681328. Read it at Google Books - Find it at Amazon 2. Ackerman TE, Levi CS, Dashefsky SM et-al. Interstitial line: sonographic finding in interstitial (cornual) ectopic pregnancy. Radiology. 1993;189 (1): 83-7. Radiology (abstract) - Pubmed citation 3. Kaakaji Y, Nghiem HV, Nodell C et-al. Sonography of obstetric and gynecologic emergencies: Part I, Obstetric emergencies. AJR Am J Roentgenol. 2000;174 (3): 641-9. AJR Am J Roentgenol (full text) - Pubmed citation 4. Rastogi R, Gl M, Rastogi N et-al. Interstitial ectopic pregnancy: A rare and difficult clinicosonographic diagnosis. J Hum Reprod Sci. 2008;1 (2): 81-2. J Hum Reprod Sci (link) - Free text at pubmed - Pubmed citation 5. Akrivis Ch, Varras M, Kyparos J et-al. Early ultrasonographic diagnosis of unruptured interstitial pregnancy: a case report and review of the literature. Clin Exp Obstet Gynecol. 2003;30 (1): 60-4. - Pubmed citation 6. Lin EP, Bhatt S, Dogra VS. Diagnostic clues to ectopic pregnancy. Radiographics. 2008;28 (6): 1661-71. doi:10.1148/rg.286085506 - Pubmed citation 7. interstitial pregnancy. Am. J. Obstet. Gynecol. 2010;202 (1): 15-29. doi:10.1016/j.ajog.2009.07.054 - Pubmed citation 8. Walid MS, Heaton RL. Diagnosis and laparoscopic treatment of cornual ectopic pregnancy. Ger Med Sci. 2010;8 doi:10.3205/000105 - Free text at pubmed - Pubmed citation 9. Chukus A, Tirada N, Restrepo R et-al. Uncommon Implantation Sites of Ectopic Pregnancy: Thinking beyond the Complex Adnexal Mass. Radiographics. 2015;35 (3): 946-59. doi:10.1148/rg.2015140202 - Pubmed citation Edit Article Share ArticleView Revision History URL of Article Article Information rID: 1510 System: Obstetrics Section: Pathology Tags: cases, abr certifying ultrasound, emergency medicine Synonyms or Alternate Spellings: Interstitial ectopic Angular ectopic pregnancy Interstitial pregnancy Cases and Figures Case 1 Case 1Drag here to reorder.Case 2Case 2Drag here to reorder.
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