Figure 1: This complex pineal-region teratoma demonstrates areas of solid and cystic change and calcification on CT (top left) and areas of hyperintense fat signal intensity on the T1-weighted MR image (top right). Heterogeneous enhancement is a hallmark finding that illustrates the complexity of teratomas on T1 after contrast administration (bottom).
Basic Description
- Midline intracranial tumor arising from multipotential germ cells
Pathology
- Contains tissue from all three germ cell types: ectoderm, endoderm, and mesoderm
- Fat, calcification, teeth, soft tissue, sebaceum, and cysts
- Three types
- Mature: well-differentiated, WHO grade 1, often with cystic tumor component
- Immature: intermediate differentiation
- Malignant: malignant degeneration of immature teratoma, may contain somatic tumors
Clinical Features
- Arises during fetal development due to aberrant formation of the primitive streak
- Mean patient age at diagnosis 15 years; may be detected on fetal ultrasound
- Male gender predilection (4:1)
- Laboratory findings: increased serum carcinoembryonic antigen (CEA) ± α-fetoprotein
- Common presenting signs/symptoms: macrocephaly/hydrocephalus, Parinaud’s syndrome
- Treatment: surgical resection
- Prognosis: majority are lethal in utero or during 1st week of life; patients with malignant teratomas have poor 5-year survival (<20%)
Imaging Features
- General
- Midline intracranial mass
- Pineal region, sellar/suprasellar, basal ganglia, and spine
- Mass effect on tectum, optic chiasm, and hypothalamus common
- Contains calcifications, solid and fluid/cystic components and fat
- Size variable, may be large in neonates (holocranial mass)
- CT
- Heterogeneous and containing very low-density fat, hyperdense calcification (teeth), intermediate density soft tissue, and low-density cysts
- Soft tissue may enhance on contrast-enhanced CT
- MRI
- T1WI: Heterogeneous hyperintensity due to fatty components and calcification
- T2WI: Iso- to hyperintense soft tissue, cysts/fluid; variable hyperintense peritumoral edema
- T2*GRE: Hypointense signal blooming in areas of calcification
- DWI: Diffusion restriction due to hypercellular solid components
- T1WI+C: Soft tissue components enhance, nonenhancing fatty or calcified portions
Imaging Recommendations
References
Kralik SF, et al. Diffusion imaging for tumor grading of supratentorial brain tumors in the first year of life. AJNR Am J Neuroradiol. 2014;35:815-823.
Liang L, et al. MRI of intracranial germ-cell tumours. Neuroradiology. 2002;44:382-388.
Liu Z, et al. Imaging characteristics of primary intracranial teratoma. Acta Radiol. 2014;55:874-881.
Noudel R, et al. Intracranial teratomas in children: the role and timing of surgical removal. J Neurosurg Pediatr. 2008;2:331-338.
Osborn AG, Salzman KL, Jhaveri MD. Diagnostic Imaging (3rd ed). Philadelphia, PA: Elsevier, 2016.
Sawamura Y. WHO histological classification of tumors of the central nervous system: germ cell tumors (WHO, 1993). Intracranial Germ Cell Tumors. 1998:3-4.
Zygourakis CC, et al. Management of central nervous system teratoma. J Clin Neurosci. 2015;22:98-104.
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