Endometrium



Endometrium





30.1 Endometrial Polyps


Description and Clinical Features

Endometrial polyps are fairly common lesions that can occur at any age. They can be pedunculated or broad-based, are generally benign, and, if benign, have little potential to become malignant. In a woman of menstrual age, polyps can cause intermenstrual bleeding, menorrhagia (heavy menstrual bleeding), or infertility. In the postmenopausal woman, the most common symptom of polyps is vaginal bleeding.

When a woman presents with abnormal vaginal bleeding, endometrial tissue sampling using either a suction catheter (“office endometrial biopsy”) or dilation and curettage is often performed. These sampling techniques, however, can miss polyps entirely because they blindly sample a portion of the endometrium. Ultrasound and saline infusion sonohysterography (SIS) can be used to detect polyps, after which the polyps can be resected under hysteroscopic or sonographic guidance.


Sonography

On ultrasound, endometrial polyps are either homogeneously echogenic (Figure 30.1.1) or complex lesions with echogenic tissue and one or more cysts (Figure 30.1.2). If blood or secretions are present in the uterine cavity, the polyp appears as a focal mass outlined by fluid (Figure 30.1.3). Color Doppler of a polyp typically reveals a single feeding vessel (Figures 30.1.1 to 30.1.3).






Figure 30.1.1 Endometrial polyp. A: Sagittal transvaginal view of the uterus demonstrates an echogenic mass (calipers) in the endometrium, representing a polyp. B: Color Doppler demonstrates a single feeding vessel (arrow) into the polyp.

A polyp should be suspected when ultrasound demonstrates a focal area of endometrial thickening, and should be included in the differential diagnosis when ultrasound demonstrates diffuse endometrial thickening. In either of these situations, the diagnosis can be

confirmed using SIS, which depicts polyps as focal projections of endometrial tissue into the saline-filled uterine cavity (Figure 30.1.4). 3D ultrasound can also assist in definitively diagnosing uterine polyps (Figure 30.1.5).






Figure 30.1.2 Endometrial polyp containing cysts. (A) Sagittal (SAG UT) and (B) coronal (COR UT) transvaginal views of the uterus demonstrate several cysts (*) in the endometrium (arrowheads), suggesting that the structure filling the endometrium is a polyp. C: Color Doppler reveals a single feeding vessel into the polyp (arrow).






Figure 30.1.3 Endometrial polyp surrounded by fluid. A: Sagittal transvaginal view of the uterus demonstrates a polypoid projection of tissue (arrow) surrounded by fluid (F) in the uterine cavity. The fluid likely represents blood or secretions. B: Color Doppler demonstrates a single feeding vessel (arrow) into the polyp.






Figure 30.1.4 Endometrial polyp depicted by saline infusion sonohysterography. A: Sagittal midline transvaginal view of the uterus demonstrates focal homogeneous thickening of the endometrium (calipers), measuring 16.6 mm in thickness, at the fundus. B: After instillation of saline into the uterine cavity, a polyp (arrow) is seen outlined by saline (S) as it protrudes into the cavity.






Figure 30.1.5 Endometrial polyp depicted by 3D sonography. A: Sagittal midline transvaginal view of the uterus demonstrates a rounded mass in the endometrium (arrows). B: Coronal reconstruction from 3D ultrasound clearly demonstrates that the mass is a polyp (calipers) within the endometrium (arrows). The fundus is at the top of the image (arrowheads). C: 3D rendering of a different patient showing a polyp (arrowheads) projecting into the endometrial cavity (arrows).

When an endometrial polyp is present, ultrasound is most likely to detect it if the surrounding endometrium is thin or hypoechoic. Thus, polyps are most easily detected
in a postmenopausal woman or during the proliferative stage of the menstrual cycle in a premenopausal woman. They are most likely to be missed during the secretory phase of the menstrual cycle, when they may be indistinguishable from the normal thick echogenic endometrium.






Figure 30.1.6 Prolapsing polyp. A: Transvaginal color Doppler image of vascular mass (arrows) protruding from the cervix. B: Sagittal color Doppler view of lower uterine segment and cervix showing blood vessels in the stalk (arrowheads) feeding the prolapsed polyp (arrow).

Polyps can be pedunculated within the endometrial cavity and can be propelled toward the cervix by uterine contractions. Sometimes, the polyp may prolapse through the cervix and become visible on speculum examination. Blood flow in the stalk to the prolapsing polyp can be imaged with color Doppler (Figure 30.1.6).

When the endometrium is thickened and heterogeneous with many tiny cystic spaces, the differential diagnosis includes a large polyp, endometrial hyperplasia, and cancer. Color Doppler imaging is helpful in determining the diagnosis, since polyps will have a single feeding vessel (Figure 30.1.7), while hyperplasia and cancer are typically fed by multiple small vessels.






Figure 30.1.7 Large polyp with single feeding vessel. A: Sagittal transvaginal image of uterus in patient with postmenopausal bleeding showing thickened endometrium (calipers) containing multiple small cysts. B: Color Doppler image showing large, single feeding vessel (arrows) to the endometrial polyp filling the endometrial cavity.



30.2 Endometrial Hyperplasia


Description and Clinical Features

Endometrial hyperplasia refers to abnormal proliferation of the endometrial glands. It is usually caused by unopposed estrogen stimulation, which can result from estrogen given as hormone replacement therapy, hormonal disorders (e.g., polycystic ovary syndrome), or estrogen-producing tumors. Endometrial hyperplasia can also occur in patients treated for breast cancer with selective estrogen-receptor modulators such as tamoxifen.

Hyperplasia is usually a diffuse endometrial process. It can occur with or without cellular atypia. If cellular atypia is present, there is a risk of progression to endometrial carcinoma. The risk is far lower in the absence of atypia.

Endometrial hyperplasia can occur in women of any age. It generally presents with abnormal vaginal bleeding and is among the most common causes of such bleeding.


Sonography

The typical sonographic appearance of endometrial hyperplasia is diffuse, as opposed to focal, thickening of the endometrium. The thickened endometrium is usually homogeneous in echogenicity (Figure 30.2.1), but it may have multiple small cysts (Figure 30.2.2). The latter appearance is most commonly encountered in cases of endometrial hyperplasia that develop in response to treatment with tamoxifen. With tamoxifen-induced endometrial hyperplasia, cysts may also be seen at the endometrial–myometrial junction (Figure 30.2.3).

Endometrial hyperplasia is best detected when the normal endometrium is expected to be thin: in a premenopausal woman during the proliferative phase of the menstrual cycle or in a postmenopausal woman. During the secretory phase of the menstrual cycle, the presence of endometrial hyperplasia is likely to be missed sonographically, because hyperplastic endometrium and normal secretory endometrium have similar sonographic appearances.

In a postmenopausal woman not on hormone replacement therapy, a sonogram to assess for endometrial hyperplasia can be performed at any time. In a postmenopausal woman on sequential hormone replacement therapy, the findings of endometrial hyperplasia can best be seen shortly after progesterone withdrawal bleeding, when the endometrium is expected to be at its thinnest.






Figure 30.2.1 Endometrial hyperplasia. A: Sagittal transvaginal view of the uterus demonstrates thickening of the endometrium (calipers, 1.97 cm), which is fairly homogeneous in appearance. B: After instillation of saline into the uterine cavity, the endometrium (calipers) is seen to be diffusely thick, consistent with endometrial hyperplasia.







Figure 30.2.2 Endometrial hyperplasia with cysts. A: Sagittal transvaginal view of the uterus demonstrates thickening of the endometrium (calipers, 1.85 cm), which contains multiple small cysts (arrows). B: Color Doppler shows minimal flow within the thickened endometrium (arrows) and no feeding vessel.

When ultrasound demonstrates diffuse thickening of the endometrium, endometrial hyperplasia should be included in the differential diagnosis, along with endometrial polyps and carcinoma. SIS and color Doppler can provide additional diagnostic information. The SIS finding that is characteristic of endometrial hyperplasia is a saline-filled uterine cavity surrounded in its entirety by diffusely thick endometrial tissue (Figures 30.2.1 and 30.2.3), which rules out a focal lesion such as a polyp. Color Doppler of endometrium hyperplasia typically shows flow within the endometrium but no single feeding vessel (Figure 30.2.2), helping differentiate it from a polyp. A definitive diagnosis of endometrial hyperplasia, however, can only be made by tissue sampling (office biopsy or dilation and curettage).






Figure 30.2.3 Endometrial hyperplasia from tamoxifen. A: Transverse view of the uterus of a patient on tamoxifen showing a thickened endometrium (arrows) centrally containing multiple small cysts. In addition, several subendometrial cysts (arrowheads) are visible at the endometrial–myometrial junction. B: Sonohysterography shows uniform endometrial thickening (arrows) and several subendometrial cysts (arrowheads).

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Feb 2, 2020 | Posted by in GYNECOLOGY | Comments Off on Endometrium
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