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 as a result of 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 syndrome
• Treatment: surgical resection
• Prognosis: majority are lethal in utero or during first week of life; patients with malignant teratomas have poor 5-year survival rate (<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 is variable, can be large in neonates (holocranial mass)
• CT
  • Heterogeneous and contain very low-density fat, hyperdense calcification (teeth), intermediate-density soft tissue, and low-density cysts
  • Soft tissue may enhance on contrast-enhanced CT imaging
• MRI
  • T1WI: heterogeneous hyperintensity due to fatty components and calcification
  • T2WI: isointense 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

• MRI without and with intravenous contrast including fat-suppressed sequences; CT imaging to detect calcification

For more information, please see the corresponding chapter in Radiopaedia.

Contributor: Rachel Seltman, MD

DOI: https://doi.org/10.18791/nsatlas.v1.03.01.40

References

Kralik SF, Taha A, Kamer AP, 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. doi.org/10.3174/ajnr.A3757.

Liang L, Korogi Y, Sugahara T, et al. MRI of intracranial germ-cell tumours. Neuroradiology 2002;44:382–388. doi.org/10.1007/s00234-001-0752-0.

Liu Z, Lv X, Wang W, et al. Imaging characteristics of primary intracranial teratoma. Acta Radiol 2014;55:874–881. doi.org/10.1177/0284185113507824.

Noudel R, Vinchon M, Dhellemmes P, et al. Intracranial teratomas in children: the role and timing of surgical removal. J Neurosurg Pediatr 2008;2:331–338. doi.org/10.3171/PED.2008.2.11.331.

Osborn AG, Salzman KL, Jhaveri MD. Diagnostic Imaging (3rd ed). Elsevier, Philadelphia, PA; 2016.

Sawamura Y. WHO histological classification of tumors of the central nervous system: germ cell tumors (WHO, 1993). In Sawamura Y, Shirato H, de Tribolet N. (eds), Intracranial Germ Cell Tumors. Springer, Vienna, Austria; 1998;3–4. doi.org/10.1007/978-3-7091-6821-9_2.

Zygourakis CC, Davis JL, Kaur G, et al. Management of central nervous system teratoma. J Clin Neurosci 2015;22:98–104. doi.org/10.1016/j.jocn.2014.03.039.