Diagnostic ultrasound ( PDFDrive )

CHAPTER 35 The Fetal Spine 1239
B
SCT
S
SCT
SCT
A B C
FIG. 35.22 Sacrococcygeal Teratoma. (A) Sagittal sonogram shows type II sacrococcygeal teratoma (SCT) that is predominantly external but
has a substantial intrapelvic component. The tumor extends up to level L5 and displaces the fetal urinary bladder (B) anteriorly. Note the calciications
(arrows) within the tumor. (B) T2-weighted sagittal magnetic resonance image demonstrates the extent and internal structure of the sacrococcygeal
tumor (SCT); S, stomach. (C) Lateral radiograph in a different neonate. (A and B courtesy of Drs. Fong, Pantazi, and Toi, Mt. Sinai Hospital, Toronto.)
Large masses may displace and distort neighboring structures,
such as the rectum and urinary bladder (see Fig. 35.22). Compression
of the distal ureters may cause hydronephrosis. Larger solid
tumors may develop substantial arteriovenous shunting, causing
fetal cardiac failure and hydrops. 120 he development of hydrops
in the presence of a sacrococcygeal teratoma carries a poor
prognosis. 120-124
PRESACRAL FETAL MASS
he diferential diagnosis of a presacral fetal mass also includes
chordoma, anterior myelomeningocele, neurenteric cyst, neuroblastoma,
sarcoma, lipoma, bone tumor, lymphoma, and rectal
duplication. Amniotic luid AFP is oten elevated in sacrococcygeal
tumor, and AChE is oten present in the amniotic luid. hese
results exclude most other causes, except a myelomeningocele.
Presacral Masses
Sacrococcygeal teratoma
Chordoma
Anterior myelomeningocele
Neurenteric cyst
Neuroblastoma
Sarcoma
Lipoma
Bone tumor
Lymphoma
Rectal duplication
If a fetal sacrococcygeal teratoma is suspected from prenatal
sonograms, serial sonograms should be arranged to monitor the
pregnancy to assess for complications, especially signs of fetal
cardiac failure. Complete fetal assessment should also include
the internal characteristics of the tumor, the size of the tumor,
and associated fetal anomalies.
For masses less than 4.5 cm in diameter, without associated
abnormalities, vaginal delivery is considered. For masses greater
than 4.5 cm diameter, cesarean section may be considered because
of the risk of dystocia and hemorrhage during vaginal delivery.
In utero surgery for arteriovenous shunting has been described
for treatment of fetal hydrops from congestive heart failure in
early pregnancy (<30 weeks), but this should be considered only
in experienced hands. 120,121
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