The patient was a 27-week-gestation female fetus, born to a 30-year-old, gravida 2, para 1 Hispanic woman by an emergency cesarean section. The early prenatal history was uneventful. The mother was O Rh-positive, antibody screen negative, rapid plasma reagin nonreactive, hepatitis B surface antigen negative. Maternal serum alpha fetoprotein done at 16 weeks was normal with multiple of the median 0.71. An ultrasound done at 16 weeks' gestation was also normal.
The mother presented with complaints of abdominal pain and distention and was in preterm labor. On physical examination, fundal height was 38 cm and a large fetal head was palpated. The fetus was in a breech position and had a heart rate of 140 beats per minute. Fetal ultrasound confirmed fetal macrocephaly. The fetal head circumference was 49.6 cm (expected head circumference for 27 weeks is 25 cm), and biparietal diameter was 12.4 cm (expected biparietal diameter for 27 weeks' gestation is 6.7 cm). The fetal brain parenchyma appeared diffusely heterogeneous with speckled areas of low echogenicity. The midline structures and ventricles could not be discerned. The fetal skull appeared thin and flexible with compression by the transducer. Amniotic fluid volume was within normal limits.
The mother subsequently underwent an emergency cesarean section for cephalo-pelvic disproportion. During delivery of the head, there was skull rupture with extrusion of the intracranial contents followed by death of the baby. A complete autopsy was performed.
At autopsy, the body weighed 2544 g. Radiograph taken at the time of autopsy showed the fetal head to be massively enlarged in proportion to the trunk (Figure 1, arrows). There was rupture at the site of the anterior fontanel with extrusion of intracranial contents. The ears were low set and there was bilateral proptosis. The pupils measured 0.5 cm bilaterally. Generalized soft tissue edema and ascites were present.
A 930-g, 17 × 15 × 9-cm intracranial mass was situated anteriorly and superiorly in relation to the brain and lay separate from the brain (Figure 2; thick arrows point to the mass, thin arrows point to the brain). The precise site of origin of the mass could not be determined. The brain weighed 160 g and both cerebral hemispheres could be discerned. A malformed brain stem was attached to the foramen magnum. Other distinct anatomic structures such as the pineal gland and third ventricle could not be identified due to autolysis. On gross examination, the mass had a variegated appearance consisting mostly of soft, tan tissue with areas of hemorrhage, cartilaginous tissue, and cystic spaces (Figure 3, formalin-fixed coronal section of the mass). The consistency ranged from rubbery firm to soft and cystic. There was no extracranial extension of the mass. Histologically, the mass was composed predominantly of immature neuroepithelial tissue forming rosette-like structures and tubules (Figure 4). The mass also contained cystic spaces lined by columnar epithelium, sebaceous glands, cartilage, smooth muscle, and pancreatic acini. Cytokeratins AE1/3 and CK 8–18 stained the epithelial component. The neuroepithelial component stained with vimentin, further confirming the primitive nature, and was not reactive with neuron-specific enolase, synaptophysin, chromogranin, and cytokeratin immunostains. The various mesenchymal components expressed S100 (cartilage), smooth muscle actin (smooth muscle), and vimentin.
Systemic findings included bilateral pleural and peritoneal effusions. The liver weighed 90 g (expected to be up to 50 g) due to increased extramedullary hematopoiesis and congestion. The heart was mildly enlarged, weighing 9.3 g (expected to be up to 8 g). The placenta was 935 g and contained hydropic chorionic villi. The umbilical cord was trivascular. The remaining organs were unremarkable.
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Pathologic Diagnosis: Congenital Immature Intracranial Teratoma With Skull Rupture and High Output Cardiac Failure
On extensive examination of the mass, there was no malignant germ cell component. The findings of generalized edema, bilateral pleural and peritoneal effusions, cardiomegaly, hepatomegaly, increased extramedullary hematopoiesis, and hydropic placenta were consistent with nonimmune hydrops fetalis. Although draining vessels were not identified in the tumor, high output cardiac failure due to shunting of blood within the massive tumor is the most likely explanation for the hydrops.
Intracranial teratomas are rare and make up 0.5% of all brain tumors and 2% of brain tumors in infants and children.1 However, teratomas make up one third to one half of all congenital brain neoplasms.2,3 Approximately 50 cases of congenital intracranial teratomas have been reported in the literature.2,4 Congenital intracranial teratoma of massive proportions is a rare event. Two reviews of massive intracranial teratomas by Vraa-Jensen5 in 1974 and Nanda et al6 in 1991 listed 11 cases, and since then, massive intracranial teratomas have been limited to individual case reports.
Teratomas are germ cell neoplasms composed of tissues from at least 2 of the 3 germ layers—ectoderm, mesoderm, and endoderm. Teratomas most probably arise from migrating foci of totipotential cells that have escaped organizing influences in early development. The location of teratomas corresponds with the eventual embryonic resting sites of these primitive totipotential cells.3 Intracranial teratomas are second to sacrococcygeal teratomas in frequency in the perinatal age group.7 Congenital intracranial teratomas arise from midline supratentorial structures such as the pineal gland, third ventricle, and quadrigeminal plate.2,3 This is in contrast with the infratentorial location of brain tumors in older children. However, in 50% of cases, it is difficult to ascertain the exact site of origin due to the massive size and resulting distortion of brain structures, as was true in our case.
Mothers present with rapid increase in abdominal girth due to macrocephaly and polyhydramnios, which is present in 50% of cases.2 Cephalopelvic disproportion can occur as early as the second trimester. The babies present with signs of hydrocephalus such as stupor, vomiting, large head, and respiratory distress. Three distinct clinical patterns of perinatal intracranial teratomas have been described: massive tumors replacing the intracranial contents, small tumors obstructing the ventricles and causing hydrocephalus, and tumors with extension into the orbit and neck.6 Infants can also present with signs of nonimmune hydrops fetalis such as generalized edema, effusions, cardiomegaly, hepatomegaly, increased extramedullary hematopoiesis, and hydropic placenta. This is most likely the result of cardiac failure secondary to vascular shunts within the tumor.8
Ultrasound has emerged as a valuable diagnostic tool in prenatal detection of these tumors. The diagnosis is usually suspected because of rapidly increasing fundal height and polyhydramnios. The ultrasonographic features of intracranial teratoma include cranial enlargement and distortion of normal brain architecture by an intracranial mass of mixed densities with solid and cystic areas, with or without foci of calcification.2,9
Congenital intracranial teratomas are associated with a high rate of stillbirth and perinatal death.2 The cause of death includes teratoma effacing the brain, dystocia, and cranial rupture during delivery. Isaacs2 reported that, of 49 cases of fetal and newborn intracranial teratomas, only 3 were alive, 16 were stillborn, 7 had intrapartum death, and in the remaining cases, survival ranged from 9.5 hours to 2 years. Long-term survival depends on complete surgical excision. Successfully treated cases are rare and the treatment success was largely attributed to the location and resectability of the tumor.
The World Health Organization divides intracranial teratomas into 3 histologic variants, that is, mature, immature, and teratoma with malignant components. Immature neuroglial tissue makes up a large portion of most teratomas that are present at birth. Perinatal intracranial teratomas contain mature and immature tissues but lack malignant germ cell tumor components. Cytogenetically, the karyotype of teratomas is identical to the host.10
Thus, our case represents a rare presentation of an extremely rare tumor associated with massive growth, skull rupture, and high output cardiac failure. Historically, cases with similar presentation to ours have shown an exponential tumor growth, predominant neuroepithelial component on microscopy, and an extremely poor prognosis.
References
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