The Term “Cornual Pregnancy” Should be Abandoned - HD

Introduction

Hello, I'm Dr. Oksana Altaic, professor of radiology from Thomas Jefferson University in Philadelphia, Pennsylvania.

The topic of this talk is the term cornal pregnancy should be abandoned, and this is my proposition. I'd like to explain that to you.

Definition and Confusion Surrounding Cornual Pregnancy

The term cornal pregnancy has means basically that there is a pregnancy occurring in the cornal portion of the uterus in the horn portion of the uterus. Cornew meaning horn, cornua is the plural of that term.

So the pregnancies that cause a mass effect or bump from the external surface of the uterus have been called corneal pregnancies.

Now, some of us use interstitial pregnancy and corneal pregnancy interchangeably, and we have, for many years, especially in the United States, some other physicians say that cornal should only refer to pregnancy that occurs in the cornal of a bicornuate or septate uterus. The Europeans use that a lot.

Other people say that corneal pregnancy is in the corn of the uterus that is in the superolateral angle of the cavity. They call that an angular pregnancy. Whether the uterus is normal or anomalous, this term is not that well known. In the United States, the radiologists are not all that familiar with this term, angular pregnancy.

However, the term was actually coined in 1898 by Kelly, a surgeon.

So you can see that corneal is imprecise and confusing. It means different things to different clinicians, which has different implications for treatment for all of the different types of quote, cornal pregnancies.

So I propose that the term corneal pregnancy should not be used. We should be much more descriptive, and that term basically should be abandoned so that a patient does not get the wrong treatment or so that there's no miscommunication among clinicians and radiologists.

The Five Cornual Pregnancies

So in fact, there are five corneal pregnancies or pregnancies that occur in the corneal region. Two of these are ectopic pregnancies.

So here we have the interstitial ectopic pregnancy, and then we have the ectopic pregnancy, which is occurring in the horn of a rudimentary uterus, which may not have a connection to the endometrial cavity or which may have a connection to the endometrial cavity.

And then there are three intrauterine pregnancies. So here is a pregnancy occurring in that superolateral angle of the endometrial cavity. This is an intrauterine pregnancy called the angular pregnancy by some.

And here's a bico uterus with a pregnancy in one horn or cornew. And here is the septate uterus, which also has a pregnancy occurring in one of the horns.

So there you have it, the five corneal pregnancies, two of which are ectopic pregnancies, the interstitial ectopic, and the rudimentary hor ectopic. And then three of them intrauterine pregnancies, the one that has been called angular pregnancy, the one in the cornal of a septate uterus, and the one in the cornal of a bico uterus.

Interstitial Ectopic Pregnancy

So let's look at the corneal ectopic pregnancies. So the interstitial ectopic pregnancy occurs in two to 4% of all ectopic pregnancies.

So the conceptus implants in the interstitial part of the fallopian tube that passes through the corneal muscular portion of the uterus. It creates a bulge in the superolateral fundal margin.

Now, here's a three DA representation of how the endometrium suddenly continues into a thin tube. And that's the beginning of the interstitial part of the tube.

Now these ectopic pregnancies rupture a little bit later than usual, less around 12 weeks or so, and they can result in fatal massive hemorrhage. That's why we have to pay attention.

Now, some of these have been called cornal pregnancies, but we should be calling them interstitial ectopic pregnancies.

So what's the difference? Well, the main premise is that the fallopian tube does not have an endometrial lining, therefore, it does not have a dece base ssus layer, and that does not interact with the pregnancy the way it does in the uterus.

So the trophoblast that grows or the conceptus in the interstitial part, the trophoblast grows right through the mucosa, invades through the muscularis and the ci rosa, and almost acts like a placenta accreta or a morbidly adherent placenta.

So there are abnormal attachments of this placenta, which then leads to rupture.

So years ago, Ackerman described the interstitial line sign, which is a line that extends from the endometrial cavity, and it points to the ectopic gestational sac. However, in our experience, this is a quite a rare kind of sign. It's very difficult to see this sign. And so you can look for it. We always do look for it, but I think what is more important is to look for a hypoechoic band of myometrium between the endometrial echoes and the gestational ectopic sac.

Here, you can see it on another patient. We have a break in the myometrium, and then we have the bulge and the gestational sac. Here's another example. There's the interstitial ectopic pregnancy, and we have a band of hypoechoic myometrium separating the two.

I think that's a much more valuable sign. We often talk about the Thin and Myometrial band around the interstitial pregnancy, but I would suggest to you that it is more important to look for the myometrial band on the side towards the uterus, and document that'll really help you make a decision.

There are mimics of an interstitial ectopic pregnancy. The number one mimicker is the pedunculated myoma. That's degenerating. That can certainly look like a gestational sac.

Here's another example, given to me by Dr. Cullen in one of the greats in ultrasound who has who's no longer with us. What helps us here to decide on this is the bridging vessels, the vessels coming from the uterus to feed this pedunculated myoma, that is in contradistinction to what happens with the interstitial ectopic pregnancy, where you have a ring of vessels around the pregnancy.

So the things that form a ring of vessels in the body are usually a gestational sac or the corpus lium. So obviously this is a pregnancy here.

Rudimentary Horn Ectopic Pregnancy

Now, the rudimentary horn ectopic pregnancy. So the malaria defect that we have here shows us that the second part, the second uterus that fuses together does not form it. It's only in a rudimentary form. You get the coordinate uterus, which has typically this banana shape.

And this little rudimentary horn could have a connection with the endometrial cavity, so they can bleed vaginally, but it may not have a connection. And the bleeding goes first into the peritoneal cavity and may not be discovered so quickly.

The pregnancy grows, and as you can see here from this article in gem that the pregnancy looks just like an ectopic growing in the tube that's hard to distinguish.

The MRIs may help us give a clue. And of course, 3D ultrasound can help us.

Now, here's a surgical specimen from a patient in our hospital. She had such a pregnancy in the horn, and this is at 10 weeks. It's started growing. There was a lot of consternation about how to handle this pregnancy because the diagnosis was very difficult. We did 3D, we did MRI.

The problem is that they usually rupture in the second or third trimester, which leads of course to fetal demise and hemorrhage. And the placenta becomes morbidly attached in the pelvis or in this region.

So usually they are excised. Sometimes they can be injected with potassium chloride or methotrexate that has been attempted, and there have even been rare reports of a delivery. But those are the ones that tend to have a thicker myometrium surrounding them.

Intrauterine Pregnancies: Angular, Septate, and Bicornuate Uterus

Now, the three cornal type pregnancies that are actually intrauterine pregnancy, so that's this term, angular pregnancy by corona uterus and septate uterus. So let's look at them.

So what is this angular pregnancy? This is not a term that we use very often. I think it is very important for you to be descriptive when you describe this more so than using that term.

So this is an implantation that occurs in the superolateral angle or corner of the endometrial cavity. If you do Mr or if you looked laparoscopically, this would be located medial to the utero tubal junction, medial to the round ligament.

Now, the gestational sac becomes eccentric, and on the surface of the uterus, there's a bump, hence the corneal term. But this pregnancy has a very good opportunity to continue growing into the endometrial cavity.

Here's a 3D representation. It's very clear that this is intrauterine. It has a broad interface with the endometrial echoes. So that's going to be our key versus the other one, interstitial ectopic, which had myometrium that we could see there.

So here's it's eccentric. It has a an adequate mantle of myometrium surrounding it. It is widely associated with the echogenic endometrium, and it is considered an intrauterine pregnancy.

Now, it's been in the literature since 1981, however, we dropped this term because we were not good at seeing these with our older equipment. It is more recently now that the term has come up in the literature because we have these high resolution transvaginal probes and 3D ultrasound.

Now, in the literature, you will find that this pregnancy is associated with spu high risk of spontaneous abortion. Uterine rupture reported up to almost 24% of cases. And abnormal placentation, that is the morbidly adherent placenta or placenta accreta.

Now the risks here possibly are higher than they actually are because a number of interstitial pregnancies have been mixed into these reports not being clear on the separation between the interstitial pregnancy and this etop this eccentrically placed gestational sac.

So many cases may have actually been interstitial ectopics. There are some reports in the literature, however, that are not showing that favorable of an outcome.

Now, the way you can think about it is the pregnancy has the opportunity to go two ways. It can continue growing into the endometrial cavity, which I think is preferred. However, for some reason, it may continue growing outward, in which case the outcome is more disastrous. And that's where the abnormal placental implantation comes about because it starts to reach towards the tube.

Now comes the intrauterine pregnancy in the cornew of a septate uterus. Now, the septate uterus is quite common. It represents 55% of uterine anomalies.

What is key is the coronal view, and that's where the three dimensional images come into play. Because we want to see a nice smooth fundal contour. We do not want to see a dip.

So once we have that, we have the we then look inside the uterus and it can have a septum, which comes partially or completely down, the complete septate or sub septate uterus.

Now, here on the 3D, you see the smooth fundal contour, and you see a division you see this angled pointed segment. That's the septum that can come way down. And on ultrasound, on a cross-sectional image, we see a shadow.

The septum does not have to be thick. It can be a thick fibromuscular band, or it can be fairly thin depending on how much muscle or fibrous tissue there is.

So here's a separation between the two horns, and that was in the septic uterus. That is an intrauterine pregnancy. Unfortunately, though it carries a high miscarriage rate.

Here's some samples. We have an eccentrically placed sac, but we do have a split here between the endometrial areas. Here's the endometrium. On one side, there's the shadowing from the septum. Here's the pregnancy in the other horn, fully engulfed by endometrium.

Here's another one. There's a separation and we have fluid, these two fluid areas. One is the sac, one is possibly bleeding, or another twin degenerating.

Now, the last cornal type is when we have a pregnancy in the horn of a bico root uterus. That is less common it rep. It occurs in 25% of end of uterine anomalies, the bico uterus. And it causes a concave, heart shaped contour on the coronal views of the uterus.

It has to have a significant dip. And then it has two separate cornua. That's very important to have a 3D or a coronal type of view to show us that it indeed has the dip.

And here we have the pregnancy in one cornew or horn and none in the other. Another case here where there's a separation shadowing from the musculature, and the pregnancy is in one horn, fully engulfed by endometrium, hence an intrauterine pregnancy.

Another example of the heart-shaped uterus. Here, we were lucky that the uterus was in such a position that we could do this on just the transabdominal image. We're usually not that lucky.

Here's a A 3D reconstruction showing the heart shape uterus with the division.

Conclusion

So I hope I've convinced you that this term corneal pregnancy could be used in five different ways. And we should be not using it because it can be confusing. We have people training moving across continents using different terminology. We should try to stick with.

Probably the best is to use a descriptive type of terminology. And I propose therefore that this term be banned.

So in summary, you should know the five types of pregnancies that occur in the cornal region of the uterus, where there is this mass effect that we can see from the outside. With eccentrically located gestational sacs, we should be able to explain their differences anatomically, and hopefully we should stop using the word corneal pregnancy.

Thank you very much for your attention.