Abstract
The ovary is an important reproductive organ in the female pelvic cavity. The ovary is small while the ovarian histoembryology, anatomy, and endocrine function are extremely complex. The type, morphology, and nature of the ovarian mass are various. The traditional diagnostic method of ovarian masses is pelvic bimanual examination. The examiners evaluate the ovarian size, shape, and texture by hand, which is difficult to detect early masses. When the masses can be palpable by bimanual examination, most patients are already in the middle and late stage of the tumor. In recent years, with the rapid development of imaging technology, CT and MRI can clearly show the mass less than 5 mm, lymph node metastasis, and ascites. However, due to the high price, it is limited to screen early ovarian masses. The serum markers for the diagnosis of ovarian cancer (CA125, AFP) are one of the screening tools for ovarian cancer, while the screening sensitivity needs to be improved.
This chapter was translated by Linlin Ma, Department of Obstetrics and Gynecology, Beijing Hospital, National Center of Gerontology, Beijing, China
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5.1 Ultrasonic Diagnosis of Uterine Leiomyomas
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(I)
Basic Concepts
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Uterine leiomyomas, commonly referred to as fibroid or myoma, are composed of amounts of smooth muscle and fibrous tissue, and the etiology is due to uterine smooth muscle cell proliferation. It is the most common benign tumor in the female reproductive system, the incidence accounting for 4–11% and 70–80% occurrence in women between 30 and 50 years old.
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Almost 80% of the uterine leiomyomas are multiple according to the pathoanatomy, sometimes even more than one hundred. Fibroids are commonly classified into two subgroups by location: corpus and cervical, of which the former accounts for about 90%. The corpus leiomyomas are classified as intramural, subserosal, submucosal, and broad ligament leiomyomas. These tumors are usually multiple and various types of leiomyomas can coexist in one uterus.
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The appearance of leiomyomas may be various which may be according to the replacement of various degenerative tissues as abnormal blood supply. The degeneration is classified into hyaline, myxoid, cystic, calcific, red, necrosis, fatty, infection, and malignant degeneration. Special types, such as cellular leiomyoma, atypical leiomyoma, mitotically active leiomyoma, and intravenous leiomyoma, are also listed here.
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The clinical manifestations are mainly related to the location and size of uterine leiomyoma. The most common symptoms include menstrual cycle changing, abdominal mass, and compression symptoms. The majority of patients complain of abnormal uterine bleeding, heavy menstrual bleeding and shortened menstrual cycle. Bowel dysfunction and bladder symptoms such as urinary frequency and urgency may be present by large fibroids.
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During physical examination, we can find an enlarged, solid uterus with an irregular contour which is consistent with fibroids. In addition, submucosal fibroids may prolapse to the endometrial cavity, cervix, or vagina.
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Ultrasonography is particularly helpful to assess the location, size, and number of myomas. Transvaginal ultrasonography provides superior resolution for fibroids smaller than 2 cm in diameter. However, ultrasonic attenuation is usually accompanied by large fibroids, and it is recommended to choose low-frequency probe and increase the gain.
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Ultrasonic diagnosis
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Enlarged or irregular-shaped uterine can be caused by multiple leiomyomas. The size and shape of the uterine are normal when accompanied by a single small intramural leiomyoma. In cases of submucosal leiomyoma or multiple leiomyomas, the uterine shape is abnormal with distorted endometrium (Figs. 5.1, 5.2, and 5.3).
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Leiomyomas may have variable appearances because of the different portions of smooth muscle and fibrous tissue. The leiomyomas can represent hypoechoic, hyperechoic, isoechoic, or punctate echo, with a typical linear shadowing effect (also known as swirling echo, Figs. 5.4, 5.5, and 5.6).
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Leiomyomas are easy to be diagnosed and measured by ultrasonography. Most represent a spherical mass, with hypoechoic or lightly hyperechoic pseudocapsule (Fig. 5.7).
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Color Doppler flow imaging shows a circular or semicircular blood flow around the leiomyomas (Fig. 5.8).
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Uterine leiomyomas occasionally undergo various forms of degeneration. The ultrasonic changes include the disappearance of normal swirling structure, hypoechoic mass, irregular cystic area in the mass, and hyperechoic area accompanied by attenuated acoustic shadowing within or around the mass. Degenerated leiomyoma is more common in pregnancy and postpartum, and often manifests as hypoechoic mass. In addition, calcification of leiomyoma usually occurs in postmenopausal women (Figs. 5.9 and 5.10).
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Special tips
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A relatively full bladder is important for transabdominal ultrasonography. Transvaginal sonography alone may fail to show the entire fibroids larger than 8 ~ 10 cm in diameter, and the combination scanning of TAS with TVS is recommended (Fig. 5.11).
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Subserosal leiomyoma with long peduncle or broad ligament leiomyoma may be misdiagnosed as ovarian mass. Pay attention to the relationship between the leiomyoma and the ovary (Fig. 5.12).
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Cystic degenerated leiomyoma should be distinguished from adnexa cyst and pregnant sac (Fig. 5.13).
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The leiomyoma should be distinguished from adenomyosis, uterine hypertrophy, endometrial polyp, adnexa mass, and uterine malformation, etc. (Fig. 5.14, 5.15, 5.16, 5.17, and 5.18).
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Typical cases
5.2 Sonographic Features of Adenomyosis
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Basic concepts
Adenomyosis is characterized by the endometrial glands and stroma are present in the myometrium, which is combined with a proliferation of smooth muscles and fibrous tissues. The etiologies are commonly reported as chronic endometritis and trauma in the myometrium which is secondary to multiple gravidity and deliveries. Adenomyosis was called internal endometriosis previously.
Adenomyosis commonly occurs in 30–50 years old multipara and 50% of the patients coexists with leiomyoma. Adenomyosis may coexist with pelvic and other organic endometriosis, also known as external endometriosis.
Adenomyosis affects the myometrium diffusely and shows as an enlarged global uterus. The diffuse or focal lesions in the myometrium are clarified and the lesions often locate in the posterior myometrium. It leads to more thickened posterior myometrium than the anterior. The ultrasonic display of focal adenomyosis, sometimes called adenomyoma, is similar to leiomyoma. While the former shows indistinct demarcate, island glands and stroma are visible in the myometrium under a microscope.
The symptoms of adenomyosis are characterized by progressive dysmenorrhea, menometrorrhagia, menostaxis, and even infertility. Some patients are asymptomatic. A diffusely enlarged and solid uterus can be palpable, accompanied with tenderness sometimes.
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Sonographic features
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Sonogram shows a diffused enlarged uterus in a normal shape or globular shape. In general, the uterus shows a longer length, width, and anteroposterior diameter (Fig. 5.21).
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Most patients with adenomyosis represent a thickened posterior myometrium and the endometrium is distorted forward or backward (Fig. 5.22).
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Thickened myometrium usually represents hyperechoic. The ultrasonic display of focal adenomyosis is similar to leiomyoma but shows an indistinct border with peripheral myometrium (Fig. 5.23).
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Sporadic and irregular tiny fluid areas are visible in the lesion during the menstrual period, which disappears after menstruation (Fig. 5.24).
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The image of diffuse adenomyosis shows that the whole myometrium is thickened, and diffusely enhanced echo. The location of the endometrium is normal (Fig. 5.25).
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Color Doppler shows that the blood flow is sporadic and stellate distributed in the focus of adenomyosis (Fig. 5.26).
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Special tips
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The ultrasound images of adenomyosis and hysteromyoma are extremely similar. Except to consider the clinical manifestations, we should pay more attention to the boundary of the lesion and surrounding muscle.
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Transvaginal ultrasonic scanning is recommended to identify the lesion boundary and endometrium in multipara patients (Fig. 5.27).
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5.3 Ultrasonic Diagnosis of Endometrial Carcinoma
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Basic concepts
Endometrial carcinoma, one of the three common malignant reproductive tumors in females, accounts for 20–30% of the malignant reproductive tumors in females. The incidence is related to race and region. According to recent statistical data, the incidence of endometrial carcinoma increases, which is most prevalent in patients aged 58–61.
The exact cause of endometrial carcinoma remains unclear. The high-risk factors include long-term and continuous endometrial stimulation by exogenous or endogenous estrogen, endometrial hyperplasia, obesity, hypertension, diabetes, unmarried, nulliparous, delayed menopause, genetic factors, etc.
The pathological findings of endometrial carcinoma are mainly divided into the diffuse type and localized type. Most of the lesions of localized type locate in the fundus of the uterus, especially near the uterine cornu. In the early stages, the endometrium shows a rough surface, the lesions are superficial and small without a mass. Sometimes, a pathological section could probably not find an obvious carcinoma lesion, which might be due to the previous diagnostic curettage or multiple curettages. Diffuse endometrial carcinoma involves a wide range of endometrium or multifocal lesions. Localized carcinoma shows polypoid or cauliflower-like growth in the uterine cavity. The common cell types of endometrial carcinoma include endometrioid adenocarcinoma (accounting for 70–80% of endometrial carcinoma), adenocarcinoma with squamous epithelial differentiation, special types such as serous papillary carcinoma and clear cell carcinoma, etc. The typical metastasis of endometrial carcinoma involves myometrial invasion, lymphatic invasion, vascular invasion, and advanced hematogenous metastasis, etc.
The typical clinical symptoms are intermittent or persistent postmenopausal vaginal bleeding. Premenopausal patients usually complain of increased menstrual volume, prolonged menstrual period, or intermenstrual bleeding. Some patients manifest with vaginal discharge, while bloody and pyometra discharge with the strong stench in advanced patients. The cervical invasion of tumor may lead to obstruction of the cervical canal, resulting in hematocele or pyometra in the uterine cavity and manifesting lower abdominal pain. In the late stages, it may cause pain in the lower abdomen and lumbosacral region which is related to the tumor invasion of surrounding tissue or compression of the mass.
In the early stages, most patients do not have any obvious systemic symptoms or signs. The enlarged and softened uterus could be palpated. Irregular nodular masses around or beside the uterus could be found in advanced patients.
The diagnosis of endometrial carcinoma is based on the pathological results of curettage.
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Ultrasonic diagnosis
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In the early stages of endometrial carcinoma, doctors could not find obvious endometrial morphologic changes by ultrasonographic image. Some patients with endometrial carcinoma only show slightly thickened endometrium or fluid in the uterine cavity (Fig. 5.28).
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Sonographic image finds enlarged uterus in patients with advanced stages of endometrial carcinoma. The enlarged uterus is especially found in patients with original atrophic after menopause. The single layer of endometrium may be thicker than 0.5 cm, with an irregular solid mass in the uterine cavity in some cases (Fig. 5.29).
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When the infiltration is involved into the myometrium, the endometrial-like echo extends to the myometrium. Endometrial carcinoma may also obstruct the cervical canal, resulting in irregular hyperechoic findings in the cervical canal (Fig. 5.30).
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An ultrasonographic image shows fluid, hematometra, and pyometra in the endometrial cavity, due to the obstruction of the cervix (Fig. 5.31).
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Special tips
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For postmenopausal women with the single layer of endometrial thickness ≥ 0.4 cm, or unevenly thickened, or space-occupying lesions; or premenopausal women with menstrual disorder accompanied by menometrorrhagia, it is advisable to carry out the diagnostic dilatation and curettage as soon as possible (Fig. 5.32, 5.33, 5.34, and 5.35).
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Endometrial carcinoma should be distinguished from endometrial hyperplasia, submucous myoma, endometrial polyp, senile endometritis, uterine effusion, and functional uterine bleeding.
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Classic cases
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A reproductive woman represented with irregular vaginal bleeding for 3 months. Ultrasonography shows a space-occupying mass in the uterine cavity, which is suspected residue, and endometrial carcinoma is confirmed by pathological examination after curettage (Fig. 5.36).
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An elderly woman, with no vaginal bleeding, represented an obvious fluid area in the uterine cavity, without thickened endometrium. The uterine effusion and endometrial carcinoma were confirmed by diagnostic dilation and curettage (Fig. 5.37).
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5.4 Ultrasonic Diagnosis of Benign Endometrial Lesion
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Basic concept
Endometrial polyp is a common tumor-like lesion, which is composed of local hyperplasia of endometrial glands and stroma. Endometrial polyps with pedicles grow into the uterine cavity. Some of the pedicels are relatively long, even protruding to the internal cervical os. It can occur at any age, especially in women aged 50–60 years.
Histologically, endometrial polyp has smooth surface, sometimes complaint as hemorrhage, necrosis and ulceration when accompanied by infection. It can be single, multiple, or diffuse lesions with different shapes and ranges from millimeters to centimeters. Pathologically, it can be divided into functional, nonfunctional, adenomyomatous, and postmenopausal endometrial polyps. The pedicles are different in thickness and length.
The typical clinical manifestation is menometrorrhagia or spotting bleeding. A single small polyp can be asymptomatic.
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Ultrasonic diagnosis
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The uterus is normal or slightly enlarged, without morphology change.
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Space-occupying lesion is visible in the uterine cavity, with discontinued or distorted endometrium. Most of them are hyperechoic, round, or punctate, attached to the inner wall of the uterine cavity, and well-defined with the endometrium (Figs. 5.38 and 5.39).
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Special tips
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Transvaginal ultrasound is recommended to show the morphology of the endometrium. Ultrasound images show abnormally thickened endometrium in the cases of diffuse heterogeneity polyps. Sonohysterography is helpful to distinguish between the endometrial polyps and endometrial thickening.
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Endometrial polyps should be differentiated from endometrial hyperplasia, submucous myoma, endometrial carcinoma, and intrauterine residue (Figs. 5.40, 5.41, 5.42, 5.43, 5.44 and 5.45).
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5.5 Ultrasonic Diagnosis of Cervical Lesions
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Basic concepts
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The cervix, a part of the uterus, is mainly composed of fibrous connective tissue and a small amount of smooth muscle cells. It is cylindrical and 2.5–3.0 cm in length. The cervical canal locates in the center, and the inner membrane of the canal can secret alkaline mucus. Cervix has many defense functions, but it is vulnerable to be injured by childbirth and uterine cavity operation, leading to chronic cervicitis, which is the most common disease in gynecology.
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Due to the special characteristics of cervical anatomy and histology, the formation of the squamous columnar junction is highly sensitive to the stimulations caused by some carcinogenic factors. Cervical cell dysplasia, disordered cell arrangement, abnormal cells, and increased mitosis may exist and lead to invasive cervical cancer eventually.
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Cervical cancer is the most common malignant tumor of the reproductive tract, with a high incidence in 35–39-year-old and 60–64-year-old women. The exact cause is not completely understood. Recently, human papillomavirus (HPV) infection, especially persistent high-risk HPV infection, is considered to be the main cause of cervical precancerous lesions and cervical cancer. Other related risk factors include early childbirth, multipara, high-risk male partners, and immune suppression.
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Common histological types include squamous cell carcinoma, adenocarcinoma, squamous adenocarcinoma, spinous adenocarcinoma, clear cell carcinoma, and undifferentiated carcinoma. According to the differentiation level, cervical cancer is divided into high differentiated, moderately differentiated, and poorly differentiated carcinoma. According to the different development stages, cervical carcinoma is divided into carcinoma in situ, early invasive carcinoma, and late invasive carcinoma.
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Exogenic type, endogenic type, ulcerative type, and endocervical type are common cervical squamous cell carcinoma, which accounts for 80–85% of all cervical carcinoma. Cervical adenocarcinoma accounts for about 15%. The main metastasis of cervical cancer is direct invasion and lymphatic metastasis.
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In general, there are not any obvious clinical symptoms and signs are shown in the early stage of cervical cancer. Once manifestations are present, usually shown as vaginal bleeding and abnormal vaginal discharge. Symptoms such as frequent urination, urgent urination, constipation, edema and pain of lower limbs, and even systemic cachexia can be complained in the late-stage patients with lesions spreading to pelvic connective tissue. In advanced-stage patients, cervical cauliflower mass can be seen protruding to the vagina during the pelvic examination, with a bleeding tendency. In the endocervical types, the cervix is hypertrophic and firm, with smooth surface or superficial ulcer, cervical canal is enlarged, and depressed ulcers are visible in advanced-stage patients. Thickened and nodular parametrial tissues can be palpated in the gynecological examination, even invaded into the pelvic wall, forming a frozen pelvis.
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The main clinical symptoms of chronic cervicitis are increased vaginal discharge, hemorrhagic leucorrhea, and postcoital bleeding. When the inflammation involves other adjacent organs or spreads to the pelvis, lumbosacral pain and lower abdominal pain may occur.
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The pathological changes of chronic cervicitis include cervical erosion, cervical polyp, cervical mucositis, cervical Nabothian’s cyst and cervical hypertrophy, etc.
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Ultrasonic diagnosis
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The main ultrasonic manifestations of chronic cervicitis, including cervical Nabothian’s cyst, cervical hypertrophy, and cervical polyp.
The enlarged cervix with multiple anechoic cysts (Fig. 5.46).
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Ultrasonic images of cervical cancer.
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No obvious ultrasonic findings are shown in the early stage of cervical cancer. When the lesion grows to a certain size and protrudes to the external os or appears as a mass, the ultrasonic image shows an enlarged cervix with a diameter of more than 3 cm. The morphology of the endocervical membrane is abnormal or disappeared (Figs. 5.47 and 5.48).
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A heterogeneous, hypoechoic, or hyperechoic, irregular mass can be shown in the cervix. When the tumor infiltrates the bladder and parametrium, the ultrasonic images show an unsmooth bladder wall and irregular hypoechoic tissue around the uterus (Fig. 5.49).
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Color Doppler shows abundant blood flow in cervical cancer (Fig. 5.50).
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Special tips
5.6 Ultrasonic Diagnosis of Uterine Sarcoma
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Basic concepts
Uterine sarcoma, which is rare, is the most malignant tumor of the female genital system. Leiomyosarcoma accounts for about 0.64% of the smooth muscle tumors of the uterus, and 45–75% of the leiomyosarcoma. Leiomyosarcoma generates from the myometrium or the connective tissue in the myometrium. Uterine sarcomas are susceptible in perimenopausal women but also can occur in young women.
According to the different original tissues, sarcomas are mainly divided into the following types: (1) Leiomyosarcoma of the uterus, which arises from the myometrium or the smooth muscle fibers of the uterine vascular wall, or from the malignant transformation of uterine fibroids. (2) Endometrial stromal sarcoma, which is derived from endometrial stromal cells and divided into low-grade and high-grade malignant stromal sarcoma. (3) Malignant mixed müllerian disease, also known as carcinosarcoma, arises from residual embryonic cells or interstitial cells metaplasia.
The main clinical symptom is vaginal bleeding, which is characterized by an excessive volume of menses, irregular bleeding, or postmenopausal bleeding. The amount of the blood varies from bloody leucorrhea to purulent discharge with a peculiar smell. Some patients have no obvious symptoms and are diagnosed as palpable abdominal mass. Advanced patients may represent anemia, cachexia, lower abdominal pain, backache, and so on. Gynecological examination revealed an enlarged, irregular, and soft uterus, even occupying the whole pelvic cavity.
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Ultrasonic diagnosis
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Ultrasonic scanning shows the myoma grows rapidly within a short time, with obvious attenuation, and it is difficult to recognize the three-layer structure of the uterus (Fig. 5.53).
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A large solid mass is visible in the pelvic cavity, while the uterus is pressed to the side. Normal uterine morphology fails to be shown in some cases (Fig. 5.54).
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Ultrasonography shows heterogeneous or disordered echo in large myomas.
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Special tips
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When a patient with a history of uterine fibroids represents rapidly fibroids enlargement within a short time, it should be a concern for the clinicians. The characteristics of the uterine echo and the three-layer structure should be identified during ultrasonic scanning.
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Sarcomas should be distinguished from huge benign uterine fibroids and ovarian tumors. Women of childbearing age should be paid more attention to bilateral ovaries.
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5.7 Ultrasonic Diagnosis of Abnormal Development of Female Reproductive Organs
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Basic concepts
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At the third to fourth gestational weeks, primordial germ cells appear in the yolk-sac endoderm. At the fourth to fifth week, a genitourinary crista is formed. At the fourth to sixth week, primordial germ cells migrate to genitourinary crista to form primordial gonad. At the eighth week, primordial gonad differentiates into the ovary.
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After the gonads develop into ovaries, the mesonephric tube on the lateral side of the urogenital ridge degenerates. The head segments of the accessory mesonephric tubes on both sides form two fallopian tubes, and the middle and tail segments on both sides combine to form the uterus and the upper segment of the vagina. At the early stage of syncopation, there is still a septum, which divides the syncopation into two chambers. The septum disappears at the end of 12 weeks and becomes a single lumen. The caudal end of the accessory mesonephric duct is connected with the urogenital sinus, meanwhile, it divides and proliferates to form the vagina cavity.
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The abnormalities caused by the obstruction of normal duct formation of female reproductive organs include hymen atresia, vagina transverse, vagina mediastinum, congenital vagina atresia, and cervical atresia, etc. The abnormal uterine development caused by the hypoplasia or fusion obstacle of accessory mesonephric duct derivative includes a congenital absence of uterus, primordial uterus, uterine dysplasia (immature uterus), unicornuate uterus, uterus duplex, and uterus bicornis, saddle form uterus, mediastinal uterus, etc.
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The clinical manifestations of female congenital malformation are as follows:
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No menarche after puberty accompanied by periodic lower abdominal pain may experience following diseases, such as imperforate hymen, vaginal septum (diaphragm or oblique septum), partial atresia of the vagina and congenital cervical atresia, etc.
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No menarche after puberty should be distinguished from the following situations, such as ametria, primordial uterus, and immature uterus, etc.
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Patients with dyspareunia after marriage, recurrent abortions, premature delivery or infertility, should be examined to exclude the following conditions, such as the congenital absence of vagina, ametria, vaginal septum, vagina atresia, unicornuate uterus, uterus bicornis, and uterus septus, etc.
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Ultrasonic diagnosis
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Congenital absence of uterus is also called ametria. No uterus is visible by both TVS and TAS behind the bladder. Relatively smaller ovaries can be detected on both sides of the pelvic cavity in most patients. Congenital absence of uterus is often combined with congenital absence of vagina, resulting in the absence of vaginal gas line (Fig. 5.55).
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Rudimentary uterus. Transabdominal or transvaginal ultrasonic images show only a small cord-like hyperechoic mass behind the filled bladder. No normal uterine morphology or endometrium is shown. Ovaries can be found on both sides of the pelvic cavity in some patients (Fig. 5.56).
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Hypoplasia of uterus (infantile uterus). The uterus is shown in the pelvic cavity with a shorter anteroposterior dimension, length, and width compared to normal uterus. The anteroposterior dimension is less than 2 cm. The endometrium is unclear or in a thin line shape (Fig. 5.57).
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Uterus didephys. Ultrasonography shows two separate uterus and two separate uterine cavities. When the transabdominal ultrasonic examination is used, it should be transversely scanned from the fundus to the cervix and vagina, or from the vagina to the cervix and fundus. On the transverse view, the fundus shows like a butterfly. When moving down the probe to the uterine body, the transverse diameter of the uterine body is wider than normal. Then the two cervical canals and vaginal gas lines can be displayed when the probe is a slant to the posterior pubis. In the longitudinal scanning, place the probe on the lower abdomen and move slowly to the opposite side, two separate uteruses are displayed in turn (Figs. 5.58 and 5.59).
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Uterus bicornis or arcuate uterus. Transabdominal transverse scanning shows two uterine horns similar to the shape of sheep’s horn in the level of the fundus, accompanied by a separate uterine cavity. The lower segment of the uterine and cervix usually represents normal. When the probe is moved to scan the uterine body longitudinally, two uterus images may be shown, while only one cervix and vagina can be found. When the uterus bicornis shows a concave uterine fundus on transverse section, it is also called arcuate uterus (Fig. 5.60).
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Uterus septus. No obvious changes can be found in the contour and morphology of the uterus. The transverse images show the wider fundus with a larger transverse diameter than normal. The uterine cavity shows similarly with the shape of the Chinese character “八” or the English letter “Y.” Two separate endometriums are visible from the fundus to the cervix in the complete septate uterus, from left to right or from anterior to posterior. Partial uterus septus is characterized by the attenuated septal echo between endometrium, as the septum does not extend from the fundus to the cervix (Figs. 5.61 and 5.62).
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Rudimentary horn of uterus. A normal uterus can be seen in the pelvis with a solid mass on either side of the uterus. The echo of mass is similar to the nonpregnant uterus, without endometrium. It is easy to be confused with subserosal myoma. A small amount of fluid may be found in some rudimentary uterus. When pregnancy occurs in the rudimentary horn, the diagnosis of rudimentary horn of uterus may be considered (Fig. 5.63).
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Congenital imperforate hymen. Sonogram shows the normal uterus, saccular or oval dilatation from cervix to the vagina, with weak or enhanced echo inside. Some patients combined with uterine cavity dilatation and cervix dilatation (Fig. 5.64).
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Atrasia of vagina or vaginal septum. Sonogram shows the normal uterus, dilatated uterine cavity or cervix, and vaginal dilatation above the vaginal septum or oblique septum. Patients with a relatively longer history of the disease may accompany dilation of bilateral fallopian tube or bilateral adnexal masses, with retention of menses inside (Fig. 5.65).
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Special tips
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There are many different types of female congenital genital malformation. Various scanning methods are recommended. TAS is utilized to show the position and structure of the uterus for further diagnosis of the uterus didephys, uterus bicornis, and septate uterus. The endometrial echo is an important sign to identify uterine malformation.
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Attention should be paid to differentiate bicornate uterus and rudimentary horn uterus from subserosal myoma and ovarian mass.
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Female congenital genital malformation may be combined with malformation of urinary system, such as the absence of kidney, ectopic kidney, etc. (Fig. 5.66).
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When it is difficult to identify the malformation of uterus by two-dimensional ultrasound, sonographic hysterography can be performed to show the endometrium and uterine cavity more clearly (Fig. 5.67).
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5.8 Ultrasonic Diagnosis of Ovarian Masses in Pelvic Cavity
The ovary is an important reproductive organ in the female pelvic cavity. The ovary is small while the ovarian histoembryology, anatomy, and endocrine function are extremely complex. The type, morphology, and nature of the ovarian mass are various. The traditional diagnostic method of ovarian masses is pelvic bimanual examination. The examiners evaluate the ovarian size, shape, and texture by hand, which is difficult to detect early masses. When the masses can be palpable by bimanual examination, most patients are already in the middle and late stage of the tumor. In recent years, with the rapid development of imaging technology, CT and MRI can clearly show the mass less than 5 mm, lymph node metastasis, and ascites. However, due to the high price, it is limited to screen early ovarian masses. The serum markers for the diagnosis of ovarian cancer (CA125, AFP) are one of the screening tools for ovarian cancer, while the screening sensitivity needs to be improved.
Recently, the application of ultrasonography in the diagnosis of ovarian diseases has shown obvious advantages. Transvaginal ultrasound scanning is especially well which can clearly show the physical properties and size of ovarian masses and provide valuable information for the clinician. Transvaginal Color Doppler ultrasonography is used in the diagnosis of ovarian tumors, which can obtain clear two-dimensional images. Moreover, it is helpful for the diagnosis and differentiation of benign and malignant ovarian masses by measurement of blood flow signals and the vascular resistance index. Due to the different characteristics of ovarian masses, the ultrasonic images are complex and diverse. Meanwhile, a given disease may be shown as different images and different diseases may be revealed as similar images. As a result, it is relatively difficult to determine the type of ovarian masses by ultrasound. According to the ultrasonic characteristics and clinical and pathological changes, the ultrasonic diagnosis of ovarian masses will be discussed in this section, including non-tumor cyst and ovarian tumor.
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I.
Non-tumor cysts
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Basic concepts
Most of the non-neoplastic cysts are retention cysts due to functional changes of the ovaries, mostly appeared in women of childbearing age. They are often associated with menstrual cycle, pregnancy, and endocrine disorders, and sometimes be related to iatrogenic medication. Most of these cysts can be absorbed by their own.
The volume of ovarian non-neoplastic cyst is generally small, with a diameter of 3–5 cm. Most of them have no clinical symptoms, while some of them can cause uterine functional bleeding, or irregular vaginal bleeding, menstrual disorders and so on. If the cyst ruptures or twists, acute abdominal pain can occur suddenly. Ovarian non-neoplastic cysts include follicular cysts, luteal cysts, luteinized cysts, parovarian cysts, polycystic ovaries, fallopian tube-ovarian cysts, simple cysts, and ovarian endometriotic cysts, etc.
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Ultrasonic diagnosis
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Follicular cysts
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Mature follicles fail to rupture, ovulate, or atresia during menstrual cycles, and then the follicular fluid accumulates in the follicle cavity leading to cysts formation in females.
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The diameter of the follicular cyst is generally less than 5.0 cm, round-shaped with thin-wall, well-circumscribed, and the fluid in the cyst is clear. Unilateral cyst is more common and most of them can vanish on their own during routine observation (Fig. 5.68).
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Corpus luteum cyst.
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The disordered blood and lymphatic supply of the corpus luteum from the ovary, or the formation of the hematoma in the corpus luteum, leads to the accumulation of clear fluid in the corpus luteum and results in cysts. This kind of cyst mostly belongs to the physiological lesion. Some of them are accompanied by delayed menstruation. The cysts will disappear naturally after menstrual onset. Similar corpus luteum cyst may also occur in early pregnancy disappear during the second trimester.
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The corpus luteum cyst is mostly isolated with a translucent wall. It is usually glossy in appearance, mostly monolocular and round-shaped, with a diameter less than 5.0 cm. Color Doppler ultrasound shows abundant blood flow inside (Fig. 5.69).
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Theca-lutein cyst
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Theca-lutein cyst refers to the luteinization of theca cells on the wall of the follicular cyst, which is related to gonadal hormones from the placental, dysfunction of hypothalamic–pituitary–gonadal axis, application of ovulation induction drugs, and other factors. Theca-lutein cyst is more common in patients diagnosed as hydatidiform mole, with an incidence of 35–50%.
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Bilateral theca-lutein cysts are more common, with a diameter of 20 cm or more, while some tiny ones can only be diagnosed under the microscope. The serum β-hCG level in patients with trophoblastic disease is significantly higher than in normal pregnancy. The masses are shown as multilocular cysts with uneven surfaces and thin septa. A clear liquid is visible in the cysts, with good acoustic transmission. The theca-lutein cysts can disappear after the primary disease is cured (Fig. 5.70).
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Polycystic ovary, POC
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The basic pathological change of polycystic ovary is homogeneously enlarged bilateral or unilateral ovaries, which is 2–3 times larger than normal with a smooth surface and thick capsule. The membrane of the ovary is thickened and the cortex is widened. Multiple follicles less than 1.0 cm usually locate peripherally along the envelope as “pearl strings” sign. Microscopical images show fibrosis of the cortical surface with fewer cells and there is little mature follicle formation and ovulation.
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PCO is more common in women of adolescence and childbearing age. The ultrasonic images show the increased volume of bilateral ovaries, occasionally unilateral. The capsule is hyperechoic and thickened with multiple follicles less than 1.0 cm located peripherally along the cortex. They are in wheel-shaped or in net-like morphology. More than ten follicles can be seen on a single section with no mature follicle and no ovulation observed routinely. The ovarian medulla is acoustically enhanced. The ovaries are usually enlarged with multilocular cystoid alteration after the application of ovulation induction drugs (Fig. 5.71).
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Simple ovarian cyst.
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Ovarian simple cysts are usually monolocular, originated from follicular cysts or serous monolocular cysts which is usually not accompany by clinical manifestation. Pathologic examination cannot determine the origin of the cysts.
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Most of simple ovarian cysts are unilateral and monolocular, regular round or oval shaped, with clear boundary, thin capsule, and clear fluid inside. Generally, it is rare to vanish naturally (Fig. 5.72).
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Ovarian endometriotic cyst.
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Ovarian endometriotic cyst is one of the most common lesions in external endometriosis. About 80% of the patients are involved in unilateral ovary and 50% of the patients are involved in bilateral ovaries. In the early stage of the lesion, small purple-brown spots or vesicles can be seen on the surface and in the cortex of the ovary. With the development of the disease, a single cyst or multiple cysts can be seen on the ovary, filled with dark brown, viscous and old blood, like chocolate, also known as “chocolate cyst” clinically.
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Most patients represent dysmenorrhea and persistent pain in the lower abdomen. Progressive dysmenorrhea is usually aggravated year by year with the development of local lesions. The degree of pain is not necessarily related to the size of the lesions. About 20% of the patients do not have any obvious clinical symptoms. A few patients may have menstrual disorders. Forty percent of the patients accompany by infertility which is also a common cause of infertility.
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Ultrasonic scanning shows round, oval, or irregular cysts on bilateral or rear of the uterus in the pelvic cavity. The capsules of the cysts are thick with an unsmooth surface. Larger cysts are usually pressed by surrounding organs or adhered to the surrounding organs. The boundary is not clearly shown.
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The ultrasonic image of chocolate cyst varies according to the duration of lesion. The different echoes in the cysts include slightly hyperechoic uniform and dense spots, complex hyperechoic and weak echo, or anechoic clear liquid.
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The diameter of a chocolate cyst is about 5 ~ 6 cm, and unilateral cyst is more common. The cyst may have fissures or even ruptures which may cause exuding or spreading of the cystic fluid into the pelvic cavity. And it results in adhesion between the ovary and adjacent organs. At this time, the contour of the cyst alters or even disappears (Figs. 5.73 and 5.74).
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Special tips
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Most of the non-tumor cystic masses on the ovary are caused by the change of an ovarian function. They are usually small in size and vanish by themselves without clinical management. But its morphology is often confused with tumor cyst.
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TVS is very helpful to detect small lesions of an endometriotic cyst. However, it is easy to be misdiagnosed with other tumors due to the variety of sonograms of a chocolate cyst.
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II.
Ovarian tumors
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Basic concepts
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The ovary is a small and complex organ, which has the most tumor types. Ovarian tumor is a common tumor of gynecologic malignancies, including benign, borderline, and malignant tumor. Cystic tumors are common and most of them are benign. Solid tumors are relatively rare. Exception for primary malignant ovarian tumors, metastasis from other organs is common, too.
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Various types of ovarian malignant tumors have various pathological characteristics. The common pathological characteristics are the disorder of cell structure and arrangement, hemorrhage, and necrosis in the tumor. According to the histologic classification of ovarian tumors formulated by the World Health Organization (WHO), they are generally divided into epithelial tumors (50–70%), sex cord stromal tumors (about 5%), germ cell tumors (20–40%) and metastatic tumors (5–10%).
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Ovarian cancer is one of the three common tumors of the female reproductive system, which accounts for about 15% of gynecological cancer, only lower than cervical cancer. It can occur at any age with the peak age of 45–64 years old. The survival rate is about 25–30%. The pathogenesis of ovarian cancer is mainly related to heredity, family history, environmental factors, and endocrine factors. 20–25% of patients with ovarian cancer have a family history.
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Primary ovarian cancer can be divided into two categories: epithelial cancer and nonepithelial cancer. Metastatic tumors may metastasize from the primary malignancies of any other organs. Common metastatic tumors are common from breast, stomach, intestine, reproductive urinary tract, and other organs. The main metastasis methods are intraperitoneal implantation and lymphatic metastasis, followed by diaphragm metastasis.
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Benign ovarian tumors are mostly asymptomatic clinically. They are often found occasionally in the routine gynecological examination. The tumors are moderately enlarged, which causes abdominal distention or palpablation. Spherical masses can be palpable unilateral or bilateral adnexal areas, either cystic or solid, indicating smooth and movability by gynecological examination. The tumors can grow big enough to occupy the full pelvis, even to the abdominal cavity. And compression symptoms may occur, such as frequent urination, constipation, difficulty in breathing and cardiopalmus, etc. Abdominal distention without shifting dullness can be found. Once the clinical symptoms of ovarian cancer appear, most patients are in advanced stages. If the tumor invades or compresses the nerves, it may cause abdominal pain, backache, lower limb pain, and anemia in the late stage.
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The ovary locates in the deep pelvis, which makes it difficult to be palpable. Nowadays, reliable methods are not available for the early detection and diagnosis of ovarian tumors. Ultrasonography is a convenient and reliable noninvasive method for early detection of pelvic masses, which enables the possible early detection of ovarian tumors.
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Ultrasonic diagnosis
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The diagnosis of an ovarian tumor can be made by its characteristics of morphology and echo. Transvaginal ultrasound and color Doppler flow examination provide referable information for the primary judgment of ovarian tumor.
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The sonographic images of ovarian cystic tumors are mostly unilateral or bilateral spherical or spheroid masses. Anechoic dark area can be seen in the cyst, unilocular or plurilocular. The septum of benign multilocular cysts is thin, without blood flow in the septum. Occasionally, the inner wall of some cystic tumors is uneven, or papillary solid hyperechoic protrusions are visible (Fig. 5.75).
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The ultrasonic image of solid ovarian tumor mostly shows unilateral and moderately enlarged mass, with an unclear wall. The tumor is a homogeneous or heterogeneous solid mass, and calcification with an acoustic shadow is visible.
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Solid tumors include ovarian fibroma, Boehner’s tumor, ovarian endometrial cancer, ovarian clear cell cancer, endodermal sinus cancer, dysgerminoma of the ovary, granular cell tumor, and theca cell tumor, etc. There are many kinds of solid tumors, without specific sonographic images, which should be confirmed by pathological examination (Fig. 5.76).
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The ultrasound images of ovarian mixed tumors show the fluid, fibrous, and fatty structures inside the tumors. Fluid area, hypoechoic, hyperechoic, or attenuated echo is visible in the tumor, which is characterized by a disordered echo. The most common type of ovarian mixed tumor is ovarian teratoma, most of which have specific manifestations on the sonogram. Cystic teratomas appear variably ranging from completely anechoic to completely hyperechoic. The common images include dough sign, hair-clot sign, fat fluid level sign, and starflower sign, etc. (Figs. 5.77, 5.78, 5.79, 5.80, and 5.81).
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The size of ovarian malignant tumors varies, unilateral or bilateral. The shape is mostly irregular, spherical, or oval with an unsmooth surface. The capsules are unevenly thickened, incompletely or unclearly displayed. Complex and disordered echoes are commonly seen inside the masses. The multilocular masses are more common, with a dense and thick septum. Blood flow may be seen on the septum. Ascites are visible in the pelvic and abdominal cavity (Fig. 5.82, 5.83, 5.84, and 5.85).
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Special tips
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Ovarian tumors are complex and the ultrasonic images lack specific signs. Some different kinds of tumors may have similar images and a certain tumor may have different images. The diagnosis should be confirmed in combination with the clinical manifestations, medical history, and related auxiliary examination.
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In the ultrasonic examination of pelvic ovarian tumors, the first step is to determine the position of the uterus, in order to identify the relationship between the tumor and the uterus and to exclude the diseases of the uterus. According to ultrasonic characteristics of the tumor, benign or malignant mass was presumptive diagnosed. Once uneven or disordered mass with ascites is found in the pelvis, a related auxiliary examination should be considered to exclude malignant neoplasia.
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Solid ovarian mass should be differentiated from intramural and subserosal myoma. Cystic mass should be differentiated from a cystic change of uterine myoma. Large cyst should be differentiated from massive ascites.
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III.
Ultrasound diagnosis of other masses in pelvic cavity
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Inflammatary mass
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Basic concepts
The infection of female internal genitalia are related to postpartum or abortion, uterine cavity operation, menstrual period infection with sexually transmitted diseases, and directly spreading from inflammation of adjacent organs, which can cause infection of the pelvic internal genitalia and surrounding connective tissue as well as pelvic peritoneum.
The pelvic inflammatory diseases include acute endometritis and myometritis, acute salpingoophoritis, pyosalpinx, tubo-ovarian abscess, acute parametritis, acute pelvic peritonitis, and sepsis.
The clinical manifestations include lower abdominal pain, some severe patients may present with chills, high fever, headache, and anorexia. Increased volume and menotaxis may occur in the period, while increased leucorrhea may occur non-menstrual period. Vaginal hyperemia and purulent secretion from the cervix can be seen in gynecological examination and inflammatory mass can be palpable in the pelvis. The mass may be fluctuant and tender. Total number of leukocytes and proportion of the neutrophils can be increased obviously.
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Ultrasonic diagnosis
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Endometritis and acute myometriitis: (i). Endometrium is swollen, thickened, and hypoechoic (Fig. 5.86). (ii). Myometritis shows a slightly enlarged uterus, attenuated echo, and obvious tenderness (Fig. 5.87).
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Acute and chronic salpingoophoritis (also known as adnexitis): (1) Adnexitis is characterized by unilateral or bilateral adnexal masses, with a diameter of 4–6 cm in general. The ovary is slightly enlarged and hypoechoic, surrounded by a fluid area (Figs. 5.88 and 5.89). (2) The adnexal mass is cystic or septate cystic, with flocculent or reticular echo inside. The wall is thickened and rough. The fallopian tube can be found thickened with tenderness (Fig. 5.90).
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Pyosalpinx and tube-ovarian abscess: Unilateral or bilateral cystic masses are shown with tiny echoes or flocculent hyperechoic material inside. Masses, with unclear boundary, are adhered to both sides and posterior uterus with an obscure margin of ovary and fallopian tube. Pyosalpinx shows flaky weak echoes, and severe tenderness when touching (Figs. 5.91 and 5.92).
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Ultrasonic diagnosis of masses after pelvic surgery
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Basic concepts
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Hysterectomy or subtotal hysterectomy is carried out because of uterine diseases or ovarian tumors, and unilateral or bilateral ovaries remain. Anatomical relationships of the pelvic organs change after extensive procedures for malignant tumors. The recurrence of the tumor or inflammation and endocrine disorders may also occur. All the situations above may result in masses in the pelvis.
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Ultrasonography has been a common method in following up for postoperative patients. The vaginal stump, masses in the pelvis, ascites, and effusion between intestines should be observed when scanning.
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Ultrasonic diagnosis
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Recurrence of myoma after operation. It usually occurs in the uterine body or the residual cervix, and the mass represents solid echoes of different sizes (Fig. 5.93).
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Recurrence of ovarian or uterine malignancies. Heterogeneous or homogeneous solid mass can be found in pelvis, may be accompanied by ascites (Figs. 5.94 and 5.95).
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Lymphocyst after tumor surgery: Most lymphocysts locate in bilateral ilium fossa or the posterior part of the pelvic cavity, presenting cystic echoes and clear boundary. Most of the lymphocysts are less than 5 cm (Fig. 5.96).
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Inflammatory mass. Sonogram shows the irregular cystic mass in the adnexa area, with separated or reticular echoes. The fluid in the mass is not clear. The patient has tenderness and the mass can shrink or disappear after treatment.
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Pelvic encapsulated effusion after operation. Sonogram shows irregular mass filled with fluid, with weak tiny echoes or linear septum inside (Fig. 5.97).
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Ovary preservation. Ovary can be found in pelvic cavity. Non-tumor cysts or tumor may occur in the residual ovary (Fig. 5.98).
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Special tips
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With the widespread use and improvement of ultrasonic technology, it has been widely used in the field of gynecology. Ultrasonography can detect various pelvic masses at an early stage, which has been a routine method for pelvic examination.
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Inflammatory mass is the most common one in the female pelvis, and it is also a common disease of gynecology. No special signs could be found by ultrasonography, thus more attention should be paid to differentiate it from other ovarian masses. It is vital to undertake routine ultrasonic follow-up, combined with the clinical history and treatment.
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Due to the anatomical changes after pelvic surgery, we should pay attention to the reserved reproductive organs and their positions. Note the recurrence or metastasis in patients with malignant tumor histories.
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Yang, T., Tang, Y., He, M., Xu, H., Tian, Y. (2022). Application of Diagnostic Ultrasound in Gynecology. In: Yang, T., Luo, H. (eds) Practical Ultrasonography in Obstetrics and Gynecology. Springer, Singapore. https://doi.org/10.1007/978-981-16-4477-1_5
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