1. Imaging of congenital intracranial
tumors in fetus and infant.
Dr/ ABD ALLAH NAZEER. MD.

2. Primary central nervous system (CNS) tumors are a common group
of neoplasms in the infant population, being second only to leukemia in
frequency. CNS tumors of the fetus represent only 10% of all antenatal
tumors, ranking behind extra cranial teratomas, neuroblastomas, and soft-
tissue tumors.
Intracranial teratoma is the most common fetal brain tumor, accounting for
approximately half of all reported cases. It is followed in frequency by
astrocytomas of varying grades, lipomas, choroid plexus papillomas,
craniopharyngiomas, and primitive neuroectodermal tumors.
With regard to anatomic distribution, the majority of fetal CNS tumors are
supratentorial.
Congenital brain tumors most commonly arise from the pineal gland,
suprasellar area, or cerebral hemispheres; however, imaging or even autopsy
are frequently unable to determine the origin of these lesions. The tumors
most commonly become clinically manifest in the third trimester of
pregnancy, sometimes in patients with a normal ultrasound (US) scan
obtained recently as 2 weeks before the clinical diagnosis.
Diagnosis earlier in pregnancy, particularly before 30 weeks gestation,
portends a particularly deleterious prognosis, with reported mortality rates as
high as 96.9%.

3. Histological type and mortality rate of main CNS tumors.

4. Imaging modalities.
US and/or MRI as well as the Multislice CT Scan.
Congenital Teratoma.
Intracranial teratomas are rare, accounting for 0.5-2.0%
of intracranial tumors. They comprise 50% of congenital
brain tumors (those presenting in the first 60 days of life).
Teratomas are typically benign tumors containing
elements of all 3 germinal layers: ectoderm, mesoderm
and endoderm. They develop from embryonic cells which
become “misinvolved” during formation of the primitive
streak in the 3rd week of life. Some of these cells become
“misenfolded” as intracranial rests of tissue.

5. Contrast enhanced CT of congenital teratoma shows a centrally located
heterogeneous mass containing cystic/solid components and severe hydrocephalus.

6. Axial T1 (left) and T2 (right) images of a congenital teratoma (arrows). The mass is
centrally located and has a heterogeneous appearance. There is hydrocephalus.

7. Heterogeneous suprasellar mass lesion, proved by histopathology teratoma.

8. Right frontal teratoma with hemorrhagic component.

9. Astrocytoma of infancy.
Astrocytoma of infancy is a rare tumour that is present itself as a hemispheric
mass of voluminous size in infants. It reveals well-circumscribed dural base
mass lesion . The tumors are associated with good prognosis.
Right frontal Oligodendroglioma.

10. Desmoplastic astrocytoma of right fronto-temporo-parietal lobe.

11. juvenile pilocytic astrocytoma of the cerebellum

12. Neoplasms of the choroid plexus account
for 0.4%-0.6% of all intracranial tumors.
2%-4% of pediatric brain tumors, and 10%-20% of brain tumors
in children younger than 1 year of age. Most choroid plexus
tumors (about 80%) occur as the benign, slowly growing
choroid plexus papilloma, a WHO grade I tumor with a favorable
overall prognosis. Choroid plexus tumors have long been
associated with hydrocephalus and symptoms related to
increased intracranial pressure. In most cases, the increased
intraventricular pressure is secondary to an increase in the
production of CSF by the tumor. Histologic examination of
choroid plexus papillomas reveals an appearance quite similar to
that of normal nonneoplastic choroid plexus tissue. Prominent
fronds of fibrovascular connective tissue surrounded by columnar
or cuboidal cells without significant mitotic activity are typical.

13. Choroid plexus glomus of the lateral ventricle.

14. Choroid plexus glomus at the lateral ventricle.

16. Medulloblastoma.
Medulloblastoma is the most common malignant brain
tumor of infancy and comprises approximately 20% of all
primary central nervous system tumors occurring in
patients less than 18 years. Medulloblastoma is believed
to arise from the precursor cells of the external granule
layer of the developing cerebellum and is predominantly
composed of densely packed cells with round-to-oval
hyperchromatic nuclei with generally abundant mitotic
activity.
The etiologies of infant medulloblastoma are unknown
for most patients.

17. Axial T2 (A) and contrast-enhanced T1 (B) images of a 3-year-old with a medulloblastoma

18. Supratentorial Primitive
neuroectodermal Tumors.
Supratentorial primitive neuroectodermal tumors, by definition
occurring in the cerebrum or suprasellar region, are composed
of undifferentiated or poorly differentiated neuroepithelial
cells that may show differentiation along various cell lines.
Supratentorial primitive neuroectodermal tumors are
infrequent, accounting for approximately 2.5% of childhood
brain tumors, with peak incidence in the first 3 years of life.
Although morphologically indistinguishable from
medulloblastoma, cytogenetic and molecular genetic studies
have now demonstrated that supratentorial primitive
neuroectodermal tumors are distinct.

19. Hemorrhagic primitive neuroectodermal tumor of
the right frontal lobe in a 4-month-old infant.

21. Atypical Teratoid/Rhabdoid Tumors
Atypical teratoid/rhabdoid tumors usually present early in life and
may constitute as many as 20% of all embryonal tumors. However,
the atypical teratoid/rhabdoid tumors have been reported all
throughout childhood and into early adulthood. The clinical
presentation of atypical teratoid/rhabdoid tumors is
indistinguishable from that of medulloblastoma or supratentorial
primitive neuroectodermal tumors. About 50% of atypical
teratoid/rhabdoid tumors arise in the posterior fossa, 40% are
supratentorial, and the rest are pineal, spinal, or multifocal.67 Their
location can be intra-axial, extra-axial, or both as they often invade
through the meningeal and ependymal boundaries.
Leptomeningeal spread occurs in one third of cases at
presentation.

22. Axial T2 (A) and contrast-enhanced T1 (B) images of an 8-month-old with
a large rhamboid tumor arising in the posterior right lateral ventricle.

23. MR images of a boy with a hemorrhagic AT/RT in the frontal lobe.

24. Neonatal craniopharyngioma.
Craniopharyngioma is a rare neonatal tumor, although it is the
most common tumor of the parasellar region in childhood. Only
a few cases have been antenatally diagnosed. inception time.
Craniopharyngioma of fetus 26 weeks with supra-sellar echogenic mass.

25. Craniopharyngioma of 2 months infant.

26. Craniopharyngioma of 8 months infant.

27. Congenital craniopharyngioma.

28. Ependymomas arise from ependymal cells that line
the ventricles and passageways in the brain and the
center of the spinal cord. Ependymal cells produce
cerebrospinal fluid (CSF). These tumors are classified as
supratentorial or infratentorial. In children, most
ependymomas are infratentorial tumors that arise in or
around the fourth ventricle. According to the WHO
classification of brain tumors, ependymal tumors are
classified into the following four main subtypes:
Subependymoma (WHO Grade I).
Myxopapillary ependymoma (WHO Grade I).
Ependymoma (WHO Grade II).
Anaplastic ependymoma (WHO Grade III).

29. Post-contrast MR image demonstrating an
ependymoma in the cerebello-pontine angle.

30. Hemangioma is a common benign vascular neoplasm that
closely resembles normal vessels and can be found in all organs of
the human body. Vascular lesions can be classified as infantile
hemangiomas or vascular malformations on the basis of their
natural history, location, cellular turnover, and histologic
characteristics. Hemangiomas are the most common tumor of
infancy. It is estimated that they occur in 1%–2% of the population
in general and in up to 10% of white persons. They occur more
frequently in girls than in boys (3:1 ratio), and their prevalence is
higher in premature infants. Hemangiomas are present at birth in
30%–40% of cases, with the remainder generally being appreciated
in the first months of life. More than one-half are located in the
head and neck, with the most common sites of involvement being
the mid-cheek, upper lip, and upper eyelid.
Other common involved organ systems include: liver, central
nervous system, intestine and lungs.

31. Multiple intra-cerebral hemangioma by ultrasound study.

32. Multiple intra-cerebral hemangioma with hemorrhage.

33. Nasal gliomas occur near the root of the nose (where
the cranial portion of the nose joins the forehead), are composed
of dysplastic glial tissue, and are congenital nonneoplastic
lesions best categorized as heterotopia. A nasal glioma may be
connected to the brain by a stalk of tissue in up to 15% of cases,
but the stalk does not contain a direct fluid-filled tract that
communicates with the subarachnoid spaces. Nasal gliomas are
intranasal in 30% of cases, extranasal in 60%, and mixed in 10%.
Treatment requires surgical excision. Close follow-up of these
patients is of paramount importance because of the possibility of
postoperative CSF rhinorrhea and intracranial infectious
complication. If there is an intracranial extension that cannot be
safely and adequately repaired via the initial extracranial
approach, a frontal craniotomy is recommended to prevent any
complication. Overall, recurrence rates of 4 to 10% have been
reported.

34. MDCT shows nasopharyngeal mass lesion with extension to the
skull base and brain, proved histopathologically as nasal glioma.