Findings:

The scan on the left demonstrates a markedly enlarged, thickened and heterogeneous endometrium that proved to be endometrial carcinoma. Contrast this to the normal post-menstrual endometrium in the adjacent scan.

Discussion:

During the past decade ultrasound has played an increasing role in the evaluation of the endometrium in patients with infertility, pelvic pain and abnormal uterine bleeding. Previously, and still today, in many centers, invasive endometrial biopsy, curettage of the endometrium and hysteroscopy were and are the main methods of evaluation of these patients. While these techniques clearly have a role in the diagnostic armamentarium, they have been replaced by diagnostic ultrasound as the initial step in the investigation of the patient with abnormal uterine bleeding.

Prior to embarking upon a discussion of the techniques utilized in performing and interpreting the sonographic evaluation of the endometrium it is necessary to review the normal anatomy and physiology of the endometrium. Thanks to the early work of Fleischer et al, Forrest et al and Jones et al, we now have a better understanding of the sonographic appearances of the endometrium and uterus throughout the reproductive menstrual cycle. Much of this discussion is taken from these authors early work. The sonographic appearance of the endometrium will depend upon whether the patient is of reproductive age or post-menopausal and if of reproductive age, at what point in the menstrual cycle they are examined. The normal endometrium consists of two layers: the functional and basal layers. The uterine or endometrial cavity is the apposition of the inner aspects of the functional layers. At the junction of the basal layer and the myometrium, frequently a poorly echogenic layer is identified. This layer is inner myometrium containing a vascular network of capillaries and veins around the muscle fibers of the inner third of the myometrium. Thus at various times in the reproductive cycle one may identify the following structures: the myometrium, the "halo" of the inner myometrium, the basal endometrial layer, the functional endometrial layer and the reflection from the interface of the uterine cavity or inner functional layers.