Intracavitary Changes

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Uterus

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Female Genital Tract

Ectopic Pregnancy

In an ectopic pregnancy (1:100 intrauterine pregnancies),4 a pseudogestational sac may appear at the center of the uterus. This fluid collection is caused by a decidual reaction within the slit-like uterine cavity. The sac rarely exceeds 2 cm in diameter, lacks an echogenic rim, and does not enlarge. A mass with a hyperechoic ring and anechoic center can be demonstrated in the adnexal region. Since this usually represents a tubal abortion, a conceptus is not present.

Ectopic pregnancy occurs more frequently when an IUD is in place (Fig.13.47). It is extremely rare for an intrauterine pregnancy to coexist with an IUD: 1:35 000 pregnancies.4

Fig. 13.47 Ectopic pregnancy: thickened, hypoechoic fallopian tube (T); IUD in the uterine cavity (high-level echo, arrow).

In a missed abortion, either the chorionic cavity does not contain a conceptus or the conceptus is rudimentary and fails to develop further. The adnexa appear normal (Fig.13.48).

In an incomplete abortion, structures with irregular outlines and varying echogenicity can be demonstrated within the uterine cavity. The hyperechoic areas are retained products of conception, while hypoechoic areas represent small pockets of blood.

In some cases the remnants of an incomplete abortion may be found entirely in the cervical region (Fig.13.49). Differentiation is then required from an abnormal cervical pregnancy, which is recognized by a club-like expansion of the cervix.4

Fig. 13.48 Early pregnancy. Suspicion of missed abortion in the fifth week of pregnancy. The chorionic cavity is surrounded by the hyperechoic chorion (arrows), an embryonic area is not detectable; no progress in size. UT = fundus of the uterus.

Fig. 13.49 Incomplete abortion: remnants of the embryonic area are still inside the uterus, visible as a nonhomogeneous formation in the cervix (arrow). In the following time curettage. BL = bladder; UT = uterus.

Endometrial polyps. Like adenomas, polyps arise from local sites of mucosal hypertrophy and project into the uterine cavity. They are usually benign (Fig.13.50). They may be pedunculated, and the pedicle may be so long that the polyp protrudes from the cervical os. Endometrial polyps are usually solitary. Large polyps can form in response to increased estrogen production after menopause. Treatment in

bleeding patients consists of dilatation and curettage. Further surveillance is indicated because of the risk of carcinoma.

Sonographically, the endometrium is hyperechoic and thickened with indistinct borders (Fig.13.51, Fig.13.52). If a mucocele or serometra is present, the polyps will be clearly delineated within the anechoic or hypoechoic uterine cavity.

Cervical polyps. More common than endometrial polyps, cervical polyps are lentil-size to cherry-size growths (Fig.13.53) that may be seen in the cervical os during speculum examination. Removal of these polyps should be followed by dilatation and curettage. Cervical polyps should not be removed during pregnancy.

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Female Genital Tract

Pathological findings in the endometrium. The principal findings are as follows:

●Thickness >15 mm, or > (5–)8 mm after menopause.

●Nonhomogeneous echo pattern with microcystic or macrocystic changes, which may be benign or malignant. Cysts < 3 mm are typically benign.

●Indistinct endometrial/myometrial boundary.

A small amount of fluid in the uterine cavity does not have pathological significance.

A homogeneous endometrium more than 8 mm thick warrants ultrasound surveillance. The differential diagnosis includes hyperplasia and early endometrial carcinoma. Cytological examination is inconclusive, and the diagnosis is established by curettage.

Fig. 13.56 Endometrial layers at midcycle: hyperechoic – hypoechoic – hyperechoic – hypoechoic – hyperechoic (not illustrated). UT = uterus; M = myometrium.

Fig. 13.59 Uniformly echogenic endometrium (E) during the secretory phase after ovulation, with no central echo. Normal, circular myometrium blood flow pattern is clearly defined by power Doppler.

Fig. 13.54 Proliferative phase: endometrium with a fine central echo (arrow; first half of cycle). M = myometrium.

A bright internal echo in the uterine cavity with a homogeneous endometrium, seen particularly well in the presence of serometra, may be an endometrial polyp. This is confirmed by removing the lesion for histology.

Fig. 13.57 Endometrium at midcycle, day 14. Cursors: thickened endometrium; arrows: middle echo; BL = bladder.

Fig. 13.60 Thick, proliferative endometrium, second half of the cycle; regular thickness; endometrial thickness 20 mm.

Fig. 13.55 Endometrial layers at midcycle: hypoechoic – hyperechoic – hypoechoic. Proliferation phase.

It is normal after ovulation to find a small amount of free fluid in the rectouterine pouch, but other causes of ascites should be excluded.

Fig. 13.58 Mature graafian follicle (GF), day 14. BL = bladder; UT = uterus.

Fig. 13.61 Thick, proliferative endometrium (arrows), hyperechoic with a hypoechoic center. BL = bladder.

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Uterus

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Female Genital Tract

Cystic Glandularand Atypical Adenomatous Hyperplasia

Cystic glandular hyperplasia occurs in an anovulatory cycle with a persistent follicle.7

Atypical adenomatous hyperplasia is diagnosed histologically by curettage. It is a precancerous lesion that progresses to corpus carcinoma in 20% of cases (Fig. 13.62, Fig.13.63).

Women who take tamoxifen (antiestrogen) are at increased risk of developing endometrial carcinoma.

Endometritis, Cervicitis

Fig. 13.64 Endometritis, myometritis.

a Hypoechoic uterus with indistinct borders, a retrouterine abscess, marked tenderness to pressure, and a foulsmelling discharge.

Histology. Carcinoma of the uterine corpus is generally an endometrial cancer. The majority are adenocarcinomas (40%). Corpus carcinoma arises from the endometrium of the uterine fundus, usually in the cornual region. A typical lesion is adenocarcinoma of the endometrium with extensive squamous cell metaplasia, found in 28% of cases (these tumors are called adenocancroids or adenocanthomas). Squamous cell carcinoma of the uterine corpus is rare, accounting for less than 1% of lesions. Stromal cancers (mucosal sarcomas) can also arise from the endometrium.

Risk factors. Tumor growth is estrogen-de- pendent and is mediated by estrogen receptors on the glandular epithelial and stromal cells. This is why years of unopposed estrogen stimulation is thought to be associated with a higher risk of endometrial carcinoma (ovarian tumors, polycystic ovaries, hepatic cirrhosis, etc.).

FIGO and TNM Staging for Corpus Carcinoma

0/Tis Carcinoma in situ

I/T1 Tumor confined to the uterine corpus IA/T1a Tumor confined to the endometrium

IB/T1b Tumor invades less than half of the myometrium IC/T1c Tumor invades half or more of the myometrium II/T2 Tumor invades the cervix

IIA/T2a Spread limited to the endocervix IIB/T2b Tumor also invades the cervical stroma III/T3 Spread in the lesser pelvis

IIIA/T3a Tumor involves the serosa and/or adnexa, and/or tumor detected in ascites IIIB/T3b Vaginal involvement

IIIC/N1 Pelvic or para-aortic lymph node metastases IVA/T4 Invasion of the bladder and/or rectum

IVB/M1 Distant lymph node metastases outside the lesser pelvis

An increased risk exists in endometrial carcinoma syndrome with overweight, hypertension, and glucose intolerance or diabetes mellitus. The principal risk factor is age, and

Fig. 13.67 Endometrial carcinoma (D 2: 27.9 mm) in a postmenopausal patient. The uterus (UT, 96.4 mm long) is still just distinguishable from the myometrium by its greater echogenicity. BL = bladder.

women with a higher socioeconomic status seem to be predisposed.

Growth pattern. Corpus carcinoma grows slowly on the mucosa or may form a polypoid lesion projecting into the uterine cavity; thus it stays confined to the mucosa for some time. It eventually invades the myometrium by contiguous spread but rarely penetrates the serosa. Metastasis occurs much later than with cervical carcinoma and only after the tumor has permeated the outer third of the myometrium.

Chorioepithelioma

Choriocarcinoma (malignant chorioepithelioma) arises from syncytial and Langhans cells of the placenta following a birth (20%), miscarriage (25%), or molar pregnancy (50%). It may develop after a latent period of several years. The overall incidence of chorioepithelioma is very low (1:100 000 births).

Fig. 13.68 Endometrial carcinoma: the tumor (cursors) is just distinguishable by its higher echogenicity in the transabdominal scan.

Distant metastases are rare and occur at a late stage. Bleeding usually directs attention to the cancer while it is still confined to the uterine corpus.

Sonographic features. The sonographic hallmarks of endometrial carcinoma are as follows:

●Thick, hyperechoic endometrium

●Macrocystic changes

●Ill-defined margins

●Expansion of the uterine cavity by tumor with an exophytic growth pattern

The tumor begins with a nodule in the endometrium, which grows rapidly into the uterine wall. Chorioepithelioma is extremely malignant and metastasizes early to lung, brain, kidney, bone, etc. Bleeding is a frequent complication. Serum levels of chorionic gonadotropins and α-hCG are elevated.

Fig. 13.69 Transvaginal scan: 2 cm carcinoma (arrows) with ill-defined margins. Uterine width is 54 mm.

The uterus may be larger than normal for age. Endometrial carcinoma appears more echogenic than the myometrium. The precise assessment of myometrial invasion has a crucial bearing on the prognosis. Transabdominal ultrasound is not sufficiently precise for this purpose, but transvaginal scanning can define the myometrium with great clarity (Figs. 13.67, 13.68, 13.69).

Ultrasound shows inadequate postpartum involution of the uterus in addition to an enlarging intracavitary mass. Because of the chorionic gonadotropins from chorioepithelioma, the ovaries contain corpora lutea at various developmental stages as well as granulosa and theca-lutein cysts. As a result, cystic ovaries are frequently noted at ultrasonography.

Fig. 13.70 Cervical carcinoma: balloonlike enlarged uterine cervix (CE), well defined to the surrounding tissue. BL = bladder; UT = uterus.

myoma. An extensive ovarian cancer can also mimic cervical carcinoma.