Ultrasound of the Uterus and Endometrium

Recent ACOG Guidelines on Endometrial Thickness

A more recent opinion has been issued by the American College of Obstetricians and Gynecologist.

In that report, it was suggested that four millimeters rather than five be used as a cutoff.

I've shown here the results by using the different threshold measurements, and it is incumbent upon any particular institution to decide together which number they would use.

At UCSF, less than five millimeters in the evaluation of postmenopausal bleeding is still considered a reliable means by which to exclude cancer.

Case Examples in Postmenopausal Bleeding

Sometimes we encounter patients such as this postmenopausal bleeding presented to a gynecologist and endometrial biopsy was attempted, though was con inadequate that prompted an ultrasound, which shows this a trace of fluid in the uterine cavity.

The presence of this fluid indicates some degree of cervical stenosis trace intrauterine fluid suggesting cervical stenosis, thus explaining why the biopsy was difficult to perform.

The presence of the fluid, however, allows us to better visualize the endometrium and we see a uniform thin endometrium, single layer thickness measuring one millimeter.

No additional evaluation would be necessary for that patient.

In this patient also with postmenopausal bleeding attempted biopsy, which was inadequate, an ultrasound was performed as the next step.

This patient had fibroids limiting the visualization of the endometrium, and oftentimes cases such as this would be read as, inadequate visualization of the endometrium due to the myomas limiting the ability of ultrasound, to assess the patient's cause of bleeding.

However, in this instance where we could see the endometrium, it measured over five millimeters, in fact, seven millimeters.

So in this post-menopausal patient with abnormal bleeding, while the visualization of the endometrial stripe was limited due to the myomas where seen it measured seven millimeters prompting additional evaluation.

And in this instance, endometrial cancer was found at surgery.

Another postmenopausal patient presented with bleeding, had had a biopsy which was deemed adequate and reported benign, but had persistent bleeding.

And as I said earlier, that would prompt an additional evaluation.

In this instance, the patient had an ultrasound marked thickening of the endometrium was seen well over the cutoff values.

In fact, over 15 millimeters, it measured 20 millimeters in maximal AP diameter, additional tissue sampling was performed and this, was found to be endometrial cancer.

Endometrial Cancer Overview

Endometrial cancer is the fourth most common cancer in women.

The most common GYN cancer typically, presents in the postmenopausal patient.

Median age 61 a quarter occur before menopause.

The main risk is increased circulating estrogen.

So women who early menarchy and late menopause, luckily it tends to present in the early stage and almost always presents with vaginal bleeding.

The diagnosis is made by endometrial biopsy, which is fairly sensitive and specific.

Occasional false negatives occur due to small cancers arrive sitting in a polyp or vocalized area, localized area of the endometrium.

The treatment is surgical with hyster hysterectomy and sgo. Ooh, ooh, ectomy.

Ultrasound Evaluation in Tamoxifen Patients

We are asked to use ultrasound to evaluate patients, who have breast cancer or at increased risk for breast cancer, some of whom are being treated with tamoxifen.

The requisition might come to evaluate the ovaries, but in so doing, we would see the endometrium and might encounter an endometrial appearance such as this, a thick endometrium, heterogeneous and echo texture with multiple cysts.

The differential diagnosis for this appearance in this woman on tamoxifen would include endometrial polyp and cystic endometrial hyperplasia.

The appearance on ultrasound is not specific.

An additional evaluation might be prompted, certainly would be prompted if there is a history of bleeding.

Patients on tamoxifen have been found to have a variety of findings at pathology, and often more than one process.

The differential includes polyps, hyperplasia, and even endometrial cancer.

It's worth recognizing that some of the cysts seen are not actually within the endometrium, but represent changes of in the inner myometrium, foci of reactivated or degenerated adenomyosis in response to tamoxifen exposure.

So sub endometrial cysts may be seen worth distinguishing from the endometrial cysts and if need be, recognized by Sonohysterography to review.

Tamoxifen is used as an adjuvant hormonal therapy for patients being treated for breast cancer.

It has an anti-estrogen tumor suppressive effect in the breast, but has been found to have an agonist estrogen action on the endometrium, particularly in the postmenopausal patient.

Increased incidence of hyperplasia and cancer in these patients.

While ultrasound can be used, it can be quite misleading because of the, variable, responses of the endometrium to tamoxifen exposure.

There are a high rate of false positives, increased thickness of the endometrium, heterogeneous with cystic changes, not all of which correlate with malignant histology.

The take home message is that, that in women with abnormal bleeding, ultrasound is not a reliable maneuver and in those patients biopsy need be performed.

Incidental Findings in Asymptomatic Patients

On occasion, women are sent to evaluate the ovaries postmenopausal patient, for example, such as this.

There's no history of abnormal bleeding or symptoms related to the endometrium, but in the process of doing the pelvic sonogram, we come across a thicker than expected endometrial stripe.

This thick echogenic, endometrial stripe measuring greater than 15 in AP diameter is certainly unexpected.

In a postmenopausal woman, we would revisit the question about whether there is abnormal bleeding.

However, even in the absence of reported bleeding, an endometrium of this thickness in a patient of this age without hormone replacement therapy is unexpected and might prompt one to perform an endometrial biopsy.

In this case, that was what happened, and the biopsy revealed very early stage one endometrial cancer.

That experience where as it is, prompted us to ask the question, how thick is too thick?

If the endometrium is incidentally noted to be thick in an asymptomatic postmenopausal patient, what if anything should be done?

We realized that the, we reviewed a, our, the data asking the question, about whether a risk of cancer with different endometrial thickness in patients with and without bleeding.

Knowing that in patients with bleeding a certain thickness prompts, additional evaluation, we would assume that a thicker threshold would prompt biopsy in women without bleeding.

What we found on that review is this, in a postmenopausal woman without vaginal bleeding, if the endometrium measures more than 11 millimeters, a biopsy should be considered because the data revealed that the risk of cancer is approximately 7% similar to the threshold that prompts one to do a biopsy and a patient with bleeding and an endometrial thickness greater than five millimeters.

Again, this is a rare clinical scenario, but a useful exercise, and information worth considering.

Summary

In summary, remember the normal appearance of the endometrium in pre and postmenopausal patients in particular.

Remember that premenopausal women will undergo changes in thickness and appearance of the endometrium in the course of the monthly cycle.

Thus, evaluation of abnormal bleeding in premenopausal women is best done in the immediate postmenstrual phase.

When the stripe is uniform and thin, the technique was reviewed, how best to visualize and measure the endometrium.

That measurement and a description of the morphology should be included in the report because much rides on that, description in the evaluation of women with abnormal bleeding and in determining, the likelihood, and the ability to exclude cancer if the endometrium is well seen and appears thin, if the endometrium cannot be well seen, it should be made clear that the exam is non-diagnostic in the evaluation of abnormal bleeding and more need be done.

The risk of cancer is less than one in patients who have postmenopausal bleeding, whose endometrium is well seen, seen by ultrasound is uniform and thin.

We reviewed the sonographic appearance of polyps and myomas and the ability to delineate those by means of sonohysterography.

And it's worth, reiterating that it's important that the ultrasound, the biopsy and the clinical history be consistent.

And if not, to pursue the workup. Thank you.