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Tumors are a rare but important cause of mortality and morbidity
in the newborn. The types of tumors that occur at this age are substantially
different from those that occur in older children. Neonatal tumors
include a wide spectrum of benign and malignant tumors, some of
which have unique biologic characteristics and clinical presentations.
Tumor behavior is not always predictable and apparently benign tumors
may have a malignant potential, whereas others, malignant by histologic criteria, behave
in a benign fashion in the neonate.1
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The incidence of neonatal tumors varies from 17 to 121 per million
live births.2-4 An apparent increase in the incidence of
neonatal cancer may be due, at least in part, to the prenatal detection
by ultrasound of tumors, such as neuroblastoma, that may never present
clinically. Newborn cancer makes up about 2% of malignancies
in children.1 Tumors presenting after birth tend to be
detected early, 50% on the first day of life and many others within
the first 7 days.5,6 Fifteen to 20% are associated
with congenital anomalies and syndromes.1
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Neonatal tumors differ in distribution from those found in older
children. Table 447-1 shows the distribution
of newborn tumors from a large published series.7 Overall,
teratoma is the most common neoplasm, whereas neuroblastoma is the
most common malignancy in newborns and infants in Western countries,8,9 followed
by leukemia, sarcoma, and brain tumors. By comparison, acute leukemia
is the most common cancer in newborns in a report from Asia.9
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Neonatal Germ
Cell Tumors
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Germ cell tumors consist of a heterogeneous group of histologically benign
and malignant tumors which arise from primordial germ cells. All
subtypes can be seen in the neonate, although mature (benign) teratoma
is the most common with a reported incidence of 1 in 35,000 live
births.10
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Mature (benign) teratoma is the most common germ cell tumor in the
newborn, comprising 37% to 52% of congenital tumors.11 Malignant
elements, usually endodermal sinus tumor (EST) are found in approximately
10% of teratomas in children under age 4 months,12 but
neither the degree of histologic immaturity nor the presence of malignant
elements has correlated with recurrence or progression to malignancy.11 After
age 4 months the malignancy rate of teratomas rises, reaching almost
100% at age 3 years.12 Mature teratomas are usually
extragonadal and midline, consistent with embryonic patterns of ...