Keywords
Fetal sacrococcygeal teratoma - prenatal diagnosis - fetal surgery - prevention of
dystocia - ultrasound
Fetal sacrococcygeal teratoma (SCT) is seen in 1 in every 35,000 live births, and
it is the most common tumor presenting in newborn humans.[1]
[2] This usually benign fetal tumor develops at the base of the tailbone. SCTs derive
from the pluripotent cell line that escapes from the control of embryonic inductors.
Most SCTs are sporadic, without increased risk of aneuploidy if not associated with
other anomalies, and are found in fetuses and infants, but SCTs have been reported
in adults. The increasing use of prenatal ultrasound exams has dramatically increased
the number of fetuses diagnosed with SCT. Unlike other teratomas, an SCT sometimes
grows larger than the fetal body. Fetal SCT, if large enough, predisposes to perinatal
complications and even death due to polyhydramnios, premature birth, teratoma rupture,
bleeding, fetal hydrops, and labor dystocia.[2]
[3] In contrast, postnatal SCT carries a good prognosis with morbidity and mortality
determined largely by extent of local disease, the ratio between cystic and solid
components, and malignant potential. However, in utero fetal mortality has approached
100% when SCT is associated with fetal hydrops, which is related to high-output heart
failure secondary to arteriovenous shunting through the tumor. SCTs, especially if
not diagnosed during the pregnancy, can cause severe labor dystocia[4] with catastrophic consequences to both mother and fetus. In previous decades, the
recommended management of SCTs larger than 5 cm in diameter was delivery by cesarean
section to prevent dystocia, tumor rupture, hemorrhage, and fetal death. Rarely reported
prenatal ultrasound-guided needle drainage of cystic SCTs offers an alternative to
cesarean section that result in decreased risks for both mother and fetus.[5]
[6]
Case Reports
Case 1
A 27-year-old woman with a previous uneventful pregnancy and labor and early first-trimester
spontaneous abortion was referred to our tertiary prenatal diagnosis center for level
III ultrasound scan at gestational week 19 due to expansion in the fetal sacrococcygeal
region. The sonographic evaluation showed a singleton intrauterine pregnancy with
normal fetal biometry corresponding to the 19 + 4 gestational weeks. In addition,
a 27 × 30 × 38-mm tumorous mass arising from the sacrococcygeal region was seen. The
mass was predominantly cystic with three smaller lobes and contained some solid tissue
without significant vascularization. Otherwise, fetal morphology was normal with an
excellent biophysical profile and normal female karyotype. After counseling with the
perinatologist, geneticist, and the pediatric surgeon, the parents decided to continue
the pregnancy. The fetal growth was appropriate at the regular and frequent checkups
with no signs of hemodynamic overload due to the poor vascularization of the teratoma.
Magnetic resonance imaging (MRI) was performed at 32 weeks of gestation, which revealed
predominantly cystic type I SCT. The size of the teratoma at the last prenatal outpatient
visit was 96 × 72 × 64 mm. Its circumference was 349 mm (slightly larger than the
abdominal circumference) and the fetus was in a vertex presentation with an excellent
biophysical score and the Doppler indices. The cervix was favorable for the induction
of labor with Bishop score 5. To avoid possible dystocia during the labor, we decided
to drain the cystic parts of the SCT. The fetus was immobilized by administration
of 0.35 mL of vecuronium bromide (Norcuron®, Organon, Oss, The Netherlands) into the gluteal region, which was followed by ultrasound-guided
removal of 300 mL of clear fluid with a 22-gauge spinal needle. Successful induction
of uncomplicated labor was done by an intravaginal application of a 25-μg tablet of
misoprostol (Cytotec®, Pfizer Aps, Ballerup, Denmark). A 3870-g baby girl was born in excellent condition
with Apgar scores of 8 and 10 and umbilical artery pH of 7.27. A decompressed mass
without ulceration was seen in the sacrococcygeal region of the newborn, and the anus
and the external genitalia appeared normal and nondisplaced. The mother was discharged
home on the third postpartum day. The SCT was removed on the first postnatal day.
Tumor markers and histology revealed a mature cystic teratoma. The residual teratoma-tissue
was removed laparoscopically 2 months after birth. The infant is now 2 years, 2 months
old, and her growth and development are appropriate for her age. The only remnant
of the intrauterine process is the unremarkable scar in the presacral area.
Case 2
A 32-year-old mother of three healthy child was referred for the level III perinatal
ultrasound after a second-trimester screening due to the suspected fetal SCT and two
soft markers (intracardiac echogenic focus and short femur).Detailed ultrasound examination
showed a single male fetus with a typical type I predominantly cystic SCT with a small
and poorly vascularized solid component. Fetal morphology was otherwise normal and
the bioprofile was excellent. MRI confirmed cystic type I SCT. After prenatal counseling,
an uncomplicated amniocentesis was performed and a normal male karyotype was obtained.
The family opted for continuation of the pregnancy, which was followed in the regular
outpatient policlinic department. Fetal growth was appropriate and there were no signs
of hypervascularization of the SCT. At the last prenatal visit at term, the patient
experienced regular spontaneous contractions. The size of SCT was 11 × 9 × 17 cm and
estimated volume of 1200 mL. The on-call perinatologist performed an uncomplicated
drainage of 950 mL of clear fluid SCT with a 22-gauge spinal needle in two aspirations
with use of the vacuum aspiration, carefully avoiding the solid components of the
SCT ([Fig. 1]). The amniotomy was performed 2 hours later to augment the labor. A 3900-g baby
boy was born after the uncomplicated delivery with Apgar scores of 9 and 10 and umbilical
artery pH of 7.28. Decompressed sacrococcygeal mass with the intact covering skin
was observed ([Fig. 2]). The mother was discharged home at the second postpartum day. The SCT was removed
on the first postnatal day without complications. The cytological analysis of the
removed teratoma fluid was normal with abundant lymphocytes and some macrophages of
normal morphology without malignant or dysplastic cells. Recently, at the age of 6
months, the uncomplicated laparoscopic removal of the two small residual presacral
cysts in toto was performed. Neurobehavioral development of the infant is uneventful.
Figure 1 Case 2. The aspiration needle in the cystic teratoma.
Figure 2 Case 2. Shrunk teratoma immediately after the delivery of the baby boy. Note the
normal position of the external genitalia and the anus.
Discussion
One of the most dangerous labor complications in pregnancies complicated by fetal
SCT is dystocia due to the large size of the tumor, which can lead to the SCT rupture,
hemorrhage, and fetal death, as well as the injuries of maternal birth canal.[3]
[4]
[7] With the recent advances in perinatal care, particularly the increasing use of highly
sophisticated ultrasound equipment, it is unlikely that unexpected dystocia secondary
to this tumor will be seen by many physicians. An ultrasound examination is still
the gold standard in diagnosis, and follow-up enables determination of its type and
predictions of the outcome.[2] MRI is the supplementary method useful mostly in solid SCTs with pelvic invasion
because MRIs help surgeons better visualize the content and extent of the SCT before
performing neonatal surgery.[8] Most fetuses with giant SCT are delivered by cesarean section. However, there have
been a few reported cases of cystic SCT in drainage in term fetuses with subsequent
vaginal birth, but only three cases are well documented.[5]
[6] We have performed ultrasound-guided needle drainage of cystic SCTs to enable normal
vaginal birth, avoid possible dystocia, and prevent possible complications of the
cesarean section. The recent study of Patterson et al[9] has clearly shown that the maternal morbidity for classic cesarean was significantly
increased compared with low transverse cesarean. Additionally, the delivery mode in
the potential subsequent pregnancy is usually managed by elective cesarean section
due to the increased risk of uterine rupture. Occasionally, spontaneous rupture can
happen in nonlaboring pregnant women with a previous vertical incision. Even the elective
cesarean section in our two cases would have not eliminated the possibility of SCT
rupture, and the need for the extensive vertical incision would have been obvious
to deliver fetuses with an intact SCT. We have tried to optimize the time of the teratoma
fluid drainage just before the induction of labor when the cervix was favorable for
induction or during the onset of spontaneous labor and thus avoid complications of
the repeated procedures. Close communication among perinatologists and neonatal surgeons
and adequate facilities should be available at any time. Counseling by multidisciplinary
approach involving perinatologist, neonatologist, and neonatal surgeon reduces parental
anxiety associated with the diagnosis of fetal congenital malformation that is treatable
by neonatal surgery and eases decision making about the continuation of pregnancy.[10]
In conclusion, prenatal diagnosis has a major impact on the management of the fetus
with SCT. Peripartum ultrasound-guided needle puncture to drain a large cystic teratoma
is a safe procedure in experienced hands that minimizes the risks of soft tissue dystocia
and allows a normal vaginal delivery, lowering maternal morbidity and the risk of
tumor rupture.
Acknowledgment
We thank Professor Olavi Ylikorkala for his useful suggestions during manuscript preparation.
