CNS & pituitary tumors

Meningeal tumors

Anaplastic meningioma


Editorial Board Member: Meaghan Morris, M.D., Ph.D.
Deputy Editor-in-Chief: Chunyu Cai, M.D., Ph.D.
Valeria Barresi, M.D., Ph.D.

Last author update: 3 August 2022
Last staff update: 3 August 2022

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PubMed Search: Anaplastic meningioma

Valeria Barresi, M.D., Ph.D.
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Cite this page: Barresi V. Anaplastic meningioma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cnstumoranaplasticmeningioma.html. Accessed August 13th, 2022.
Definition / general
  • WHO 2021 definition: a meningioma with overtly malignant cytomorphology that can
    • Resemble a carcinoma, melanoma or high grade sarcoma
    • Display markedly elevated mitotic activity (≥ 12.5 mitoses/mm2, ≥ 20 mitoses/10 high power fields [HPF] of each 0.16 mm2)
    • Harbor a TERT promoter mutation or
    • Have homozygous CDKN2A / CDKN2B deletion
  • CNS WHO grade 3
  • 1 - 3% of meningiomas
  • De novo (primary) or progression from a lower grade (1 or 2) meningioma (secondary) (Neuro Oncol 2018;20:1113)
Essential features
  • Meningioma with overtly malignant cytomorphology that can
    • Resemble a carcinoma, melanoma or high grade sarcoma
    • Display markedly elevated mitotic activity (≥ 12.5 mitoses/mm2, ≥ 20 mitoses/10 HPF of each 0.16 mm2)
    • Harbor a TERT promoter mutation or
    • Have homozygous CDKN2A / CDKN2B deletion
  • CNS WHO grade 3
  • Shows either histologic or immunohistochemical evidence of meningothelial differentiation
    • At least shows focal meningothelial whorls, psammoma bodies or nuclear pseudoinclusions
    • Immunohistochemistry: epithelial membrane antigen (EMA)+ (even focal), SSTR2A+, possible focal CK AE1 / AE3+, STAT6-
  • Recurrence in 50 - 94%
Terminology
  • Also called:
    • Malignant meningioma
    • Meningothelial sarcoma (not preferred)
ICD coding
  • ICD-O: 9530/3 - meningioma, malignant
    Epidemiology
    Sites
    Pathophysiology
    Etiology
    • Risk factors may be similar to risk factors for meningioma: ionizing radiations; neurofibromatosis type 2 (Eur J Epidemiol 2020;35:591)
    Clinical features
    Diagnosis
    • Based on imaging (CT; MRI) / biopsy / resection specimen
    Radiology description
    • MRI: contrast enhancing mass with possible necrotic areas (Neurochirurgie 2021;67:193)
    • MRI: contrast enhancing dural tail sign at the perimeter
    Radiology images

    Contributed by Valeria Barresi, M.D, Ph.D.
     Extra-axial, dural mass

    Extra-axial, dural mass



    Images hosted on other servers:

    MRI

    Prognostic factors
    Case reports
    Treatment
    • Surgery followed by fractioned radiotherapy, experimental chemotherapy or peptide receptor radionuclide therapy (Lancet Oncol 2016;17:e383)
    Gross description
    • Dural based and widely variable in size
    • May be well circumscribed or readily adherent to brain parenchyma
    • Gross necrosis can be present
    Frozen section description
    • Differential diagnosis versus other tumor types: at least focal presence of psammoma bodies, meningothelial whorls or nuclear pseudoinclusions
    • Differential diagnosis versus CNS WHO grade 1 meningiomas: presence of mitoses
    Frozen section images

    Contributed by Valeria Barresi, M.D, Ph.D.
    Lobular architecture

    Lobular architecture

    Whorls

    Whorls

    Nuclear pseudoinclusions

    Nuclear pseudoinclusions

    Mitoses

    Mitoses

    Microscopic (histologic) description
    • May have frank malignant cytology resembling a carcinoma, melanoma or high grade sarcoma
    • Mitotic index: ≥ 12.5 mitoses/mm2, ≥ 20 mitoses/10 HPF of each 0.16 mm2
    • At least focal meningothelial whorls and nuclear pseudoinclusions are useful to establish meningothelial origin
    • Psammoma bodies may be present (World Neurosurg 2021;149:e877)
    • Necrosis and brain invasion may be present
    Microscopic (histologic) images

    Contributed by Valeria Barresi, M.D, Ph.D.
    Mitoses

    Mitoses

    Malignant morphology

    Malignant morphology

    Whorls

    Whorls

    Necrosis

    Necrosis


    EMA

    EMA

    CK AE1 / AE3

    CK AE1 / AE3

    H3K27me3

    H3K27me3

    Cytology description
    Cytology images

    Contributed by Valeria Barresi, M.D, Ph.D.
    Whorls

    Whorls

    Psmmoma body

    Psmmoma body

    Mitoses

    Mitoses

    Positive stains
    Negative stains
    Molecular / cytogenetics description
    Sample pathology report
    • Brain, parasagittal mass:
      • Diagnosis meningioma, subtype anaplastic, CNS WHO grade 3 (see comment)
      • Comment: Meningothelial neoplasia showing focal meningothelial whorls, patternless architecture, brain invasion and spontaneous necrosis. Mitotic index: 15 mitoses/mm2.
    Differential diagnosis
    Board review style question #1

    A dural based mass is found at the brain convexity. Histological examination shows a tumor with malignant morphology, mitotic index of 15 mitoses/mm2, EMA+, focal CK AE1 / AE3+, SSTR2A+, STAT6-. Which is the most likely diagnosis?

    1. Anaplastic meningioma
    2. Melanoma
    3. Metastasis of carcinoma
    4. Solitary fibrous tumor
    Board review style answer #1
    A. Anaplastic meningioma

    SSTR2A is the most sensitive and specific marker for meningioma, while STAT6 is the most sensitive and specific marker for solitary fibrous tumor. Focal CK AE1 / AE3 immunostaining can be found in anaplastic meningioma, whereas metastatic carcinoma features widespread CK AE1 / AE3 immunostaining.

    Comment Here

    Reference: Anaplastic meningioma
    Board review style question #2
    A mass is found in the left cerebral ventricle. Histological examination shows a tumor with focal meningothelial whorls, nuclear pseudoinclusions, mitotic index of 13 mitoses/mm2, GFAP-, Olig2-, EMA+, CK AE1 / AE3-. Which is the most likely diagnosis?

    1. Anaplastic meningioma
    2. Choroid plexus carcinoma
    3. Ependymoma
    4. Glioblastoma
    Board review style answer #2
    A. Anaplastic meningioma

    Anaplastic meningiomas can also be found in the cerebral ventricles. The presence of meningothelial whorls nuclear inclusions and EMA staining indicate meningothelial derivation. Other entities should be considered in the differential diagnosis, including glioblastoma (which is GFAP+, Olig2+), ependymoma (which is GFAP+, Olig2- and exhibits EMA dot-like staining) and choroid plexus carcinoma (which is more common in children and features widespread, strong CK AE1 / AE3 immunostaining).

    Comment Here

    Reference: Anaplastic meningioma
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