Definition and general considerations: These tumors are located inside the cranium and may have  several histological types:

• Teratomas
• Craniopharyngioma
• Meningeal Sarcoma
• Lipoma of the corpus callosum
• Oligodendroglioma
• Gangliocytoma
• Choroid plexus papilloma
• Glioblastoma

Teratoma is a tumor that originates from any of the three germinal layers.

Prevalence: Extremely rare. Teratoma is the most frequently reported.

Ultrasound features: The ultrasound appearances of intracranial tumors are similar and precise histological diagnosis from a scan is therefore almost impossible. The main reported features include:

• Complete loss of intracranial anatomy.
• The tumor may appear cystic, solid, or both.
• There is rapid growth with intra-tumor changes.
• Calcifications.
• Polyhydramnios (>50% of cases).
• Hydrocephalus.
• Pulmonary hypoplasia[1]
• High cardiac output failure[2]
• Teratoma is frequently located in the 3rd ventricle subfrontal region, or in subtemporal area.

Ultrasound scan of the fetal head. Note the large teratoma inside the brain. (arrow)

Picture of the newborn after delivery.

Prognosis: The outcome is fatal in almost all cases. Death may occur also in- utero.

References

[1] Weyerts, L.K., Catanzatite, V., Jones, M.C., Mendoza, A. Prenatal diagnosis of a gian intracranial teratoma associated with pulmonary hypoplasia. J Med Genet 1993; 30:880-2

[2] Sherer, D.M., Abramowicz, J.S., Eggers, P.C., Metlay, L.A., Sinkin, R.A., Woods, J.R. Jr. Prenatal ultrasonographic diagnosis of intracranial teratoma and massive craniomegaly with associated high-output cardiac failure. Am J Obstet Gynecol 1993; 168:97-9.