Diagnostic ultrasound ( PDFDrive )

CHAPTER 16 The Adnexa 579
TABLE 16.1 Ovarian Neoplasms
Tumor Incidence Examples
Surface
epithelial–
stromal tumors
65%-75% Serous cystadenoma/
carcinoma
Mucinous cystadenoma/
carcinoma
Endometrioid carcinoma
Clear cell carcinoma
Transitional cell tumor
Germ cell tumors 15%-20% Teratoma
Dysgerminoma
Yolk sac tumor
Sex cord–stromal
tumors
Metastatic
tumors
5%-10% Granulosa cell tumor
Sertoli-Leydig cell tumor
Thecoma and ibroma
5%-10% Uterus
Stomach, colon, breast
Lymphoma
tumors (5%-10%). Sonographically, ovarian cancer usually
presents as an adnexal mass. Well-deined anechoic cysts are
more likely to be benign, whereas lesions with irregular walls,
thick irregular septations, mural nodules, and solid elements
with low are more likely to be malignant. 131,132 Many scoring
systems and mathematical models based on the morphologic
characteristics have been proposed for distinguishing between
benign and malignant masses. However, subjective evaluation
of the ultrasound morphologic features (pattern recognition)
by an experienced interpreting physician has been shown to be
the superior method. 133,134 Using this method, a physician should
be able to distinguish benign from malignant masses in approximately
90% of cases. 135
Color and pulsed Doppler sonography have been advocated
for distinguishing benign from malignant ovarian masses. Support
is based on the premise that malignant masses, because of internal
neovascularization, will have high diastolic low. Malignant tumor
growth depends on angiogenesis, with the development of
abnormal tumor vessels. 136 hese abnormal vessels lack smooth
muscle within their walls, which, along with arteriovenous
shunting, leads to decreased vascular resistance and thus higher
diastolic low velocity. herefore the pulsatility index (PI) and
resistive index (RI) should be lower in malignant lesions. Although
many reports have found a tendency for both PI and RI to be
lower in malignant lesions, there is too much overlap to diferentiate
reliably between benign and malignant lesions in individual
patients. 137-142 Other parameters such as vessel location have been
suggested to improve the speciicity of Doppler ultrasound
assessment of ovarian masses. 143 Malignant lesions tend to have
more central low, whereas benign lesions tend to have more
peripheral low. However, Stein et al. 138 found considerable overlap,
with 21% of malignant lesions having only peripheral low and
31% of benign lesions having central low. Guerriero et al. 144
found a higher accuracy in predicting malignancy when color
Doppler ultrasound demonstrated arterial low within the solid
portions of the mass.
Studies comparing the morphologic features on sonography
with the Doppler indings found that Doppler ultrasound showed
no more diagnostic information than morphologic assessment
alone. 133,139,140,145 Valentin 133 concluded that, in experienced hands,
morphologic assessment is the best method for discriminating
between benign and malignant masses. he main advantage of
adding Doppler ultrasound would be to increase the conidence
with which a correct diagnosis is made. Others have found that
Doppler ultrasound, when added to sonographic morphologic
assessment, improves speciicity and positive predictive value. 142,146-
148
Brown et al. 149 found that a nonhyperechoic solid component
was the most statistically signiicant predictor of malignancy.
Schelling et al. 150 also found that a solid component in an adnexal
mass with central vascularity achieved high accuracy, sensitivity,
and speciicity in predicting malignancy. A meta-analysis of 46
published studies concluded that ultrasound techniques that
combine morphologic assessment with color Doppler low imaging
is signiicantly better in characterizing ovarian masses than
morphologic assessment, color Doppler low imaging, or Doppler
indices alone. 151 Doppler ultrasound is probably not needed if
the mass has a characteristic benign morphology, because
morphologic assessment is highly accurate in this group of
lesions. 138,141 Doppler ultrasound is likely valuable in assessing
the mass that is morphologically indeterminate or suggestive of
malignancy. Doppler indings should be combined with morphologic
assessment, clinical indings, patient age, and phase of
menstrual cycle for optimal evaluation of an adnexal mass. 152
Recently, contrast-enhanced TVS (CE-TVS) has been used
to evaluate ovarian tumor neovascularity. With dynamic CE-TVS,
malignant tumor neovascularity usually demonstrates more
prolonged contrast washout compared with benign tumors. he
diference in contrast enhancement patterns between benign
and malignant ovarian masses results in potential improvement
in diferentiating benign from malignant lesions with CE-TVS
compared with conventional TVS. 153
Surface Epithelial–Stromal Tumors
In the past, epithelial-stromal tumors were generally considered
to arise from the surface epithelium that covers the ovary and
the underlying ovarian stroma. It has since been proposed that
epithelial ovarian cancer is a collection of diseases arising from
varying cells of origin. Evidence suggests that the majority of
primary ovarian cancers (in particular, high-grade serous cancers)
are derived from the fallopian tube rather than the ovary. A
dualistic model that categorizes ovarian cancer into two groups
(type I and type II) has been described. Type I tumors usually
present at a low stage and include low-grade serous, low-grade
endometrioid, clear cell, and mucinous carcinomas. Type II
tumors include high-grade serous carcinomas, high-grade
endometrioid carcinomas, carcinosarcomas, and undiferentiated
carcinomas. Type I tumors tend to be clinically indolent, whereas
type II tumors are typically highly aggressive. 154,155
Epithelial-stromal tumors can be divided into ive broad
categories based on epithelial diferentiation: serous, mucinous,
endometrioid, clear cell, and transitional cell (Brenner). 50 his
group of tumors accounts for 65% to 75% of all ovarian neoplasms
and 80% to 90% of all ovarian malignancies. he mode of spread