CNS tumor
Pineal tumors
Pineoblastoma

Author: Nat Pernick, M.D. (see Authors page)

Revised: 5 September 2017, last major update January 2006

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Pineoblastoma [title]

Cite this page: Pernick, N. Pineoblastoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/cnstumorpineoblastoma.html. Accessed December 16th, 2017.
Definition / general
  • Grade IV of IV
  • Second most common pineal gland tumor after germ cell tumor
  • Usually age 20 years or less
  • Frequent CNS metastases or spinal seeding, which is the main cause of death
  • 5 year survival is 58%
  • Poor prognostic factors:
    • 7+ mitotic figures/10 HPF
    • Presence of necrosis
    • No neurofilament staining
Radiology images

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Tumor at midline of posterior brain

Partially calcified pineal mass

Homogeneous enhanced pineal tumor

Case reports
Treatment
  • Surgery, variable radiation therapy
  • Prognosis is usually poor
Gross description
  • Located in pineal gland
  • May appear well demarcated from surrounding brain tissue but usually infiltrates into surrounding structures
Microscopic (histologic) description
  • Sheets of densely packed cells with high grade (anaplastic / undifferentiated) features including high N/C ratio with minimal cytoplasm and large hyperchromatic nuclei
  • Also necrosis, frequent mitotic figures
  • Focal nuclear molding
  • Homer Wright or Flexner-Wintersteiner rosettes
  • May have lower grade features of pineocytoma and pineal parenchymal tumor of intermediate differentiation
  • Often infiltrates into surrounding structures
Microscopic (histologic) images

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Typical pineoblastoma with a fibrillar background

Histologic aspects

Highly cellular tumor

Homer Wright rosettes


Dense small nuclei and scant cytoplasm

Fibrillary, neuropil-like background

Numerous atypical mitoses


Neurofilament

GFAP

Synaptophysin

Ki67 labelling index - 30%

Cytology images

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Small blue cell neuroepithelial malignant tumor

Positive stains
Negative stains
Electron microscopy description
  • Occasional cytoplasmic dense core granules
  • Short immature cell processes
  • Occasional junctional complexes
  • No definite synapses
Electron microscopy images

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Presence of abundant filopodia and rare intercellular junctions but no definitive synapses

Differential diagnosis