Diagnostic ultrasound ( PDFDrive )

572 PART II Abdominal and Pelvic Sonography
Pregnancy-Associated Ovarian Lesions
Ovarian lesions associated with pregnancy include hyperstimulated
ovaries, ovarian hyperstimulation syndrome, theca lutein
cysts, hyperreactio luteinalis, and the rare luteoma of pregnancy. 36
Most are related to the normal or abnormal response to serum
hCG levels. Hyperstimulated ovaries are a normal response to
elevated circulating levels of hCG. Ovarian hyperstimulation is
most common in women undergoing ovulation induction.
Sonographically, the ovaries are enlarged with multiple cysts,
some of which may be hemorrhagic. he enlarged ovaries may
undergo torsion. 44 hey usually regress spontaneously during
the pregnancy.
he term ovarian hyperstimulation syndrome (OHS) is used
when the hyperstimulation is accompanied by luid shits 45 (Fig.
16.8). Clinically, three degrees of OHS are described: mild,
moderate, and severe. he mild form is associated with lower
abdominal discomfort, but no signiicant weight gain. he ovaries
are enlarged, but less than 5 cm in average diameter. Moderate
OHS presents with weight gain of 5 to 10 pounds and ovarian
enlargement 5 to 12 cm. he patient may have nausea and
vomiting. With severe OHS, there is weight gain of more than
10 pounds and the patient typically has severe abdominal pain
and distention. he ovaries are greatly enlarged (>12 cm in
diameter) and contain numerous large, thin-walled cysts, which
may replace most of the ovary. he associated ascites and pleural
efusions may lead to depletion of intravascular luids and
electrolytes, resulting in hemoconcentration with hypotension,
oliguria, and electrolyte imbalance. 46 Severe OHS is usually
treated conservatively to correct the depleted intravascular volume
and electrolyte imbalance and usually resolves within 2 to 3
weeks.
heca lutein cysts are the largest of the functional ovarian
cysts and are associated with high hCG levels. hese cysts
typically occur in patients with gestational trophoblastic disease.
However, theca lutein cysts are typically not seen in irst-trimester
diagnosis of gestational trophoblastic disease, because the hCG
level will not have been suiciently high for a long enough
time for them to develop. 47 heca lutein cysts can also be
seen in OHS as a complication of drug therapy for infertility.
Sonographically, theca lutein cysts are usually bilateral, multilocular,
and very large. hey may undergo hemorrhage, rupture,
and torsion.
Hyperreactio luteinalis is caused by an abnormal response
to circulating hCG in the absence of ovulation induction therapy.
Approximately 60% of hyperreactio luteinalis cases occur in
singleton pregnancies with normal circulating levels of hCG.
Hyperreactio luteinalis usually occurs in the third trimester or
less oten in the puerperium. he majority of patients are
asymptomatic, although maternal virilization may be seen in up
to 25% of patients. he incidence of hyperreactio luteinalis
increases in women with polycystic ovarian disease. 48 In contrast
to OHS, body luid shits are rare. Sonographically, there are
bilaterally enlarged ovaries with multiple cysts similar to OHS,
although the ovaries tend not to be as large and the condition
occurs later in pregnancy. Hyperreactio luteinalis is a self-limited
condition that resolves spontaneously.
Luteoma of pregnancy is the only solid mass in this group
of pregnancy-related processes. It is a rare benign process unique
to pregnancy that is due to stromal cells that may become hormonally
active, producing androgens and replacing the normal ovarian
parenchyma. Most patients are asymptomatic, although maternal
virilization may occur in up to 30%. hese patients have a 50%
risk of virilization of the female fetus. 49 Sonographically, luteomas
usually present as nonspeciic, heterogeneous, predominantly
hypoechoic masses that may be highly vascular. An ovarian mass
in a pregnant patient with signs of virilization should suggest
this diagnosis, because luteoma is the most common cause of
maternal virilization during pregnancy. Surgery is not indicated
since the condition resolves spontaneously, typically ater
delivery.
A
B
FIG. 16.8 Ovarian Hyperstimulation Syndrome. (A) TVS shows a greatly enlarged ovary with multiple cysts, some hemorrhagic. (B) Sagittal
sonogram in right upper quadrant shows large volume of free intraperitoneal luid.