Introduction
Congenital brain tumors are extremely rare and comprise 0.5 to 1.9%[1] of all childhood brain tumors. Among these, teratomas are the most common and constitute
one-third[2]
[3] of all such cases.
As prognosis of intracranial teratoma is poor,[4] the prenatal diagnosis and obstetric management present a great challenge for planning
and follow-up and treatment of the disease in accordance to preferences of parents.[5]
Case Report
A 29-year-old lady, G5P4L2D1, attended antenatal care in Wattayah ObGyn clinic at
23 weeks of gestation. She had previous normal deliveries. Apart from mild gestational
diabetes in the present pregnancy, there were no other comorbidities.
This was a nonconsanguineous marriage. She had two live healthy children. Her last
pregnancy had a fetus with renal agenesis and ended in intrauterine fetal death.
Anomaly scan at 23 weeks gestation showed that the fetus had a brain anomaly with
ventriculomegaly—holoprosencephaly. There was already craniomegaly and advanced biparietal
diameter corresponding to 28 weeks. This was followed by a detailed anomaly scan by
a fetal medicine consultant who reported a large intracranial tumor. The scan at 27
weeks showed a large for gestational age fetus with a weight of 2 kilos. Macrocephaly
was noted with a biparietal diameter measuring 12.24 cm and head circumference measuring
40.13 cm. Abdominal circumference was also advanced and measured 27.2 cm corresponding
to 31 weeks gestation. All long bones corresponded to 26 to 27 weeks gestation. Associated
polyhydramnios was noted. Fetal head was grossly enlarged. The entire brain was replaced
by large irregular solid and cystic areas with no normal tissue ([Figs. 1]
[2]
[3]). The fetus also showed frontal bossing and hypertelorism ([Fig. 4]). Mild ascites ([Fig. 5]), pericardial effusion ([Fig. 6]), and cardiomegaly were noted. There was mild tricuspid regurgitation but outflow
tracts were normal. Stomach bubble was small and collapsed. The spine, kidneys and
urinary bladder were normal. Impression was of a brain tumor.
Fig. 1 Ultrasound showing massive intracranial tumor with solid and cystic areas replacing
the entire brain tissue and disrupting the anatomy.
Fig. 2 Ultrasound showing the fetal head with no discernable anatomy.
Fig. 3 Ultrasound showing profile view of the fetal head showing distorted anatomy due to
the massive intracranial tumor entire brain tissue and disrupting the anatomy.
Fig. 4 Ultrasound showing hypertelorism.
Fig. 5 Ultrasound showing mild ascites: consistent with features of nonimmune hydrops.
Fig. 6 Ultrasound showing mild pericardial effusion, consistent with features of nonimmune
hydrops.
Couple was counseled about the poor prognosis. As fetus already had macrocrania, delivery
was planned at 28 weeks with the aim of avoiding cesarean section for a large head.
The aim was to achieve vaginal delivery.
Labor was induced. The fetus was in cephalic presentation. Second stage of labor was
protracted as the head remained above pelvic brim and there was no descent. Cephalocentesis
did not seem a viable option as there was more of solid tissue within the fetal cranium
rather than fluid that could be tapped. We were contemplating cesarean section for
nondescent of the fetal head but providentially there was timely spontaneous rupture
of the fetal head with the decompression of fetal skull and brain tumor tissue from
the vagina, facilitating the delivery of the head followed by the body ([Fig. 7]). At birth, the neonate was seen by the pediatrician. There were no signs of life
and it was declared as a fresh stillbirth. On gross examination, the brain tissue
was disordered, hyperplastic and had areas of hemorrhage, cystic, and necrotic changes.
Brain tissue was sent for histopathological examination and was reported as congenital
intracranial immature teratoma.
Fig. 7 Stillborn baby with decompressed cranium and massive variegated intracranial tumor
by the side.
Due to the anticipated diagnosis and poor prognosis of the fetus by prenatal scan,
the couple and medical team were prepared for the birth of anomalous baby with guarded
viability. There was great relief, both from the obstetrician and the couple, at avoiding
a cesarean scar with its associated morbidity.
Discussion
Teratomas contain tissues from all the three embryonic germ layers.[6] Though teratomas are the commonest among congenital intracranial tumors, there are
only few mentioned in literature that reached massive proportions[2]
[7] replacing the entire cerebral hemisphere of the fetus, as was seen in our case.
These are usually diagnosed in the third trimester and carry an extremely poor prognosis[5] irrespective of the malignant potential, especially if diagnosed before 30 weeks[6] of gestation. Mortality rate is quoted as high as 90 to 97%.[6]
The differentials of a large intracranial lesion include hydrocephalus, holoprosencephaly,
astrocytoma, ependymal cyst, craniopharyngioma, choroid plexus cyst, hemorrhage, arachnoid
cyst, vein of Galen aneurysm, and porencephaly.[8]
Since it usually has a sporadic occurrence, karyotyping is not necessary[5]
[9] unless accompanied by other malformations.
Precise determination of extent of tumor involvement of adjacent structures is vital
to determine the prognosis, amenability for resection and possible sequelae of surgery.[9]
Ultrasound has emerged as a major valuable tool[2]
[3] in assessing intracranial structures and differentiates between the tumor and other
abnormalities. Ultrasound and magnetic resonance imaging (MRI) appearance of intracranial
teratoma is usually of an irregular heterogeneous mass with hyperechoic and hypoechoic
features with both solid and cystic areas as well as calcified components with distorted
brain anatomy.[2]
[9]
[10]
[11] MRI can help in determining the remaining brain structures, exact location of tumor,
and differentiating from hemorrhages.[12] Both ultrasound and MRI are complementary[2] and together allow more precise diagnosis of these tumors prenatally.
Fetal MRI is not freely available at many centers. However, due to the reliability
and accuracy of information provided by ultrasound alone, we may resort to it as our
guiding modality. In our center, we were able to diagnose, predict the poor prognosis,
and manage this case solely on the basis of ultrasound expertise.
Maternal presentation is with rapidly increasing fundal height and polyhydramnios
in 50%[2]
[3] cases. Cephalopelvic disproportion can occur very early, even in the second trimester.[2]
[13] Babies present with an intracranial mass, macrocrania, hydrocephalus, and signs
of nonimmune hydrops that can be attributed to cardiac failure secondary to vascular
shunt in tumor[2]. Poor prognosis of intracranial tumor at overall survival rate of 7.8 to 10%[10]
[13] has been quoted in literature.
In our case, ultrasound reliably demonstrated gross macrocephaly with biparietal diameter
measuring as big as 12.24 cm and head circumference 40.13 cm (at 27 weeks of gestation),
loss of recognizable anatomic features due to replacement of entire brain by large
irregular solid, and cystic areas with no normal tissue, features of fetal hydrops
and polyhydramnios. Color doppler ruled out vascular tumor ([Fig. 8]). All the above features helped in predicting poor fetal prognosis.
Fig. 8 Ultrasound image with unamplified color Doppler signals over the intracranial mass
ruling out vascular tumor.
Definitive diagnosis was made by histology after birth.[1]
Causes of death due to intracranial teratomas are brain effacement by the tumor, dystocia,
and cranial rupture during delivery.[2]
[14]
During the fetal period, the skull has the remarkable ability to expand, so some congenital
central nervous system tumors can expand enormously leading to dystocia, hydrops,
and stillbirth. Large tumors may necessitate decompression of the cranium to permit
vaginal delivery.[14]
[15]
[16]
Cesarean section rate is alarmingly high almost 60%[13] in such cases.
Classic teratomas are associated with high death rates and should be conservatively
managed. If possible, medical termination of pregnancy (MTP) can be offered before
viability. Vaginal delivery should be the aim,[16] far as possible.
There are a few case reports in literature, similar to our report, wherein there have
been intracranial tumors with an exponential growth[7]
[17] with extremely poor prognosis.
Isaac[17] has reported a rare presentation of an extremely uncommon tumor associated with
massive growth, high output failure, and skull rupture. In a case report by Washburne
et al,[7] cesarean section was performed at 30 weeks of gestation for an 18 years old due
to severe hydrocephalus. Spontaneous rupture of the skull at cesarean section led
to delivery of a stillborn infant, and a congenital teratoma was found.[7]
Isaac[17] reported that of 49 cases of fetal and newborn intracranial tumors, 16 of these
fetuses died in utero and seven were stillborn. Case survival ranged from 9.5 hours
to 2 years. Only three remained alive. Location and resectability of the tumor determine
long-term survival.[17]
In another review by Robles Fradejas et al,[5] a total of 49 cases of congenital intracranial teratomas were reviewed. Among them,
electively 12 cases underwent early medical termination with misoprostol. Twenty-eight
cases were delivered by cesarean section and only nine delivered vaginally. All died
in the neonatal period except three cases, where there was intrauterine demise after
diagnosis.[5]
There have been reports in literature, whereby in majority of the cases, cesarean
section had been performed because of the large fetal head circumference.[7] Cephalocentesis does not outwardly appear to be a possible option due to the solid
nature of the intracranial tumor. But multiple reports have confirmed intrapartum
skull rupture indicating the fragile nature of skull that may be amenable to cephalocentesis[16] and helpful in skull decompression facilitating vaginal delivery. This feature of
fetal skull rupture at delivery makes consideration for vaginal delivery a viable
option even in cases of massive brain tumors.
Due to the solid nature of the tumor that was indicated by ultrasound in our case,
we did not resort to cephalocentesis as it seemed less likely to help in shrinking
the macrocephalic head. Cesarean section was being contemplated for nondescent of
the fetal head but providentially skull ruptured with immediate decompression, thereby
making vaginal delivery possible even with the huge fetal head! This incident helped
in strengthening our confidence to consider cephalocentesis or other methods to decompress
the fragile skull in fetuses with intracranial tumors, to maximize efforts at vaginal
delivery. Given the escalating rate of cesarean section worldwide, similar decisions
will help in curtailing the cesarean section rate and decreasing maternal morbidity,
especially where the fetus is known to have a poor prognosis.
Due to the poor prognosis, it becomes a great obstetric challenge to manage, plan,
follow-up, and treat the disease according to parental preferences.[5] Advancement in technology has greatly improved early diagnosis of congenital intracranial
tumors, but there has not been much headway in fetal surgery, perhaps because prognosis
for brain tumors remains poor. It is vital to have utmost precise information regarding
the tumor, nature, and extension of lesion. In addition, even when parents do not
opt for termination, the precise diagnosis provided by antenatal imaging may help
healthcare professional prepare the parents for the neonatal outcome. Fetal medicine
centers should be well equipped with multidisciplinary teams acting, in unison, to
provide better perinatal management for the prospective parents and care for fetuses
with congenital intracranial tumors.[6]
[9]
