Vols. Videos

Pineoblastoma

Last Updated: March 27, 2020

Figure 1: This pineoblastoma demonstrates invasion into the superior tectal plate on sagittal T1WI (top row left). After administration of IV contrast (top row right), the lesion demonstrates avid, heterogeneous enhancement. Axial FLAIR (bottom row left) demonstrates hyperintensity typical of most tumors. This lesion has also caused obstructive hydrocephalus at the cerebral aqueduct. ADC (bottom row right) shows low signal restricted diffusion reflecting this lesion's hypercellularity.

Figure 2: This complex cystic lesion centered in the pineal region demonstrates enhancement when comparing pre- (top row left) to post-contrast (top row right) sagittal images. The mass appears well circumscribed, a finding that may be present in pineoblastomas. They can look very similar to germ cell tumors or even lower grade primary pineal tumors. The restricted diffusion on DWI (bottom row left) and ADC (bottom row right) also implies hypercellularity of a higher-grade tumor.

Figure 3: Though centered in the pineal region, this heterogeneously enhancing lesion demonstrates the infiltrative appearance on axial and coronal post-contrast T1 (top row left, top row right) that can help to distinguish pineoblastoma from lower grade primary pineal tumors. Cystic/necrotic changes are also visible in this large lesion on sagittal T2 (bottom row).

Basic Description

  • Malignant, invasive pineal parenchymal tumor arising from embryonic pineocyte precursors (PNET)

Pathology

  • WHO grade IV
  • Invades adjacent structures often including the cerebral aqueduct
  • CSF dissemination common
  • Hypercellularity and increased mitoses are characteristic features
  • Associated with germline DICER1 mutations (DICER1 syndrome) and RB1 (bilateral retinoblastomas and pineoblastoma)

Clinical Features

  • Most commonly afflicts children in the 1st decade of life (mean age 3 years)
  • No clear gender predilection
  • Common presenting signs/symptoms
    • Hydrocephalus: headache, nausea, vomiting, altered mental status, papilledema
    • Parinaud syndrome (upgaze palsy)
    • Absent serum tumor markers (differentiates from many germ cell tumors)
  • Prognosis: poor prognosis; 5-year survival ~50%

Imaging Features

  • General
    • Lobulated, poorly-marginated pineal mass
    • May be indistinguishable from lower grade pineal tumors
    • Often larger and more invasive than pineocytomas
    • Peripheral (“exploded”) calcifications common
    • Commonly invades adjacent structures including cerebral aqueduct, corpus callosum, thalamus, brainstem, and vermis
    • May see superior displacement of cerebral veins and mass effect on the tectum
  • CT

    • Heterogeneous density, irregular pineal mass
    • Peripheral calcification
    • Variable, patchy enhancement on contrast-enhanced CT
  • MRI

    • T1WI: heterogeneously hypo- to isointense
    • T2WI: heterogeneous signal; hyperintense peritumoral edema within the surrounding brain parenchyma common
    • T1WI+C: heterogeneous enhancement
    • DWI: diffusion restriction in solid component of mass common
    • MR spectroscopy: elevated Cho, decreased NAA

Imaging Recommendations

  • MRI without and with IV contrast including both brain and spine due to risk of CSF dissemination

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

Contributor: Rachel Seltman, MD

DOI: https://doi.org/10.18791/nsatlas.v1.03.01.32

References

Cuccia V, et al. Pinealoblastomas in children. Childs Nerv Syst. 2006;22:577-585.

Gasparetto EL, et al. Diffusion-weighted MR images and pineoblastoma: diagnosis and follow-up. Arq Neuropsiquiatr. 2008;66:64-68.

Hirato J, et al. Pathology of pineal region tumors. J Neurooncol. 2001;54: 239-249.

Nakamura M, et al. Neuroradiological characteristics of pineocytoma and pineoblastoma. Neuroradiology. 2000;42:509-514.

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

Reis F, et al. Neuroimaging in pineal tumors. J Neuroimaging. 2006;16:52-58.

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