Diagnostic ultrasound ( PDFDrive )

1476 PART IV Obstetric and Fetal Sonography
A
B
C
FIG. 43.16 Maternal Floor Infarction. (A) Transabdominal sonogram
of a third-trimester placenta shows an echogenic mass (arrow) emanating
from the basal plate into the placenta. (B) In another patient, color
Doppler sonogram late in the second trimester demonstrates a placental
subchorionic cyst (arrow). (C) In another patient, highly echogenic
basal plate (arrows) suggests basal plate infarction.
he most common benign tumor of the placenta is the
chorioangioma, occurring in approximately 1% of pregnancies
(Fig. 43.19). Although most are asymptomatic, large chorioangiomas
can lead to high-output fetal cardiac failure, anemia,
hydrops, and death. 112 Chorioangiomas appear as wellcircumscribed
solid tumors in the placenta. hey can range from
hypoechoic to hyperechoic compared to the echogenicity of the
placenta. A threshold of 5 cm in diameter typically portends a
high risk for adverse outcome. 113,114 Use of color or power Doppler
ultrasound is helpful to identify increased blood low within the
solid mass, thereby distinguishing the mass as a chorioangioma.
115,116 Blood low is not consistently demonstrable, especially
with smaller chorioangiomas; those with low low tend to have
a better outcome, whereas chorioangiomas with extremely elevated
low usually are associated with adverse perinatal outcome,
commonly through high-output heart failure. hese pregnancies
require close follow-up and surveillance for polyhydramnios and
other signs of fetal hydrops. 117,118 Decreasing blood low, as
documented by color or power Doppler ultrasound, signals an
improved prognosis. 118 hree-dimensional power Doppler can
assist with the diagnosis of chorioangioma and can be used to
quantitate blood low to the tumor. 113
In cases where the fetus is at risk for hydrops, in utero
intervention improves perinatal outcomes. Interventions have
included injection of thrombogenic material, 119 microcoil
embolization, 120 and endoscopic laser devascularization, 121 in
utero transfusion, amnioreduction (for those with polyhydramnios),
and alcohol injection. 122
Maternal malignancies rarely metastasize to the placenta.
Malignant melanoma and adenocarcinoma of the breast, pancreas,
and colon are most common. 123,124 hese deposits are typically
microscopic and do not interfere with placental function.