The 2016 WHO Classification of the CNS Tumors



The 2016 World Health Organization Classification of Tumors of the Central Nervous System



Over the past decade, there has been a tremendous growth of knowledge about tumour biology and molecular genetics. Improved neurosurgical techniques, safer methods of directing radiotherapy, new chemotherapy approaches, and novel modalities of therapy provide optimism that there will eventually be improvements in treatment-related morbidity and survival. However, the current literature in neuro-oncology is still heavily influenced by publication bias and ‘gearing’, where papers are published only when they match or exceed the best of those that are already published.

The results of treatment of, for example, glioblastoma multiforme, single metastasis, or malignant meningitis appear therefore to be constantly improving, regardless of what is being achieved by the average clinician. Despite this, there are occasional well-conducted randomized controlled trials which act as a foundation on which to base management. There is increasing rigour in phase II and phase III trial methodology and governmental and private health insurance financial constraints are putting pressure on clinicians not only to prove efficacy, but also to demonstrate improved quality of life and cost-effectiveness. This trend towards evidence-based medicine and randomized controlled trials is being eroded by claims of success of new treatments on the internet, which falsely increase patient expectation and lead to difficulties with patient accrual into randomized studies. It will be interesting to see how research develops over the next decade.

Histological grading is crucial to the understanding of brain tumours and their eventual management. The World Health Organization has recently reclassified and graded brain tumours (Kleihues et al., 1993a). The WHO classification recognizes that tumours develop via different pathways and that the behaviour of some grades of malignancy are quite distinct. The classification also allows standardization of reporting for epidemiological studies. The World Health Organization has also revised its grading system of central nervous system tumours to take into account newly defined histological entities (e.g. pleomorphic xanthoastrocytoma and dysembryoplastic neuroepithelial tumours (DNET)).



Diffuse astrocytic and oligodendroglial tumors

Other astrocytic tumors

  • Pilocytic astrocytoma
    • Pilomyxoid astrocytoma
  • Subependymal giant cell astrocytoma
  • Pleomorphic xanthoastrocytoma, anaplastic pleomorphic xanthoastrocytoma

Ependymal tumors

  • Subependymoma
  • Myxopapillary ependymoma
  • Ependymoma
    • Papillary ependymoma
    • Clear cell ependymoma
    • Tanycytic ependymoma
  • Ependymoma, RELA fusion positive
  • Anaplastic ependymoma

Other gliomas

  • Chordoid glioma of the third ventricle
  • Angiocentric glioma, astroblastoma

Choroid plexus tumors

  • Choroid plexus papilloma
  • Atypical choroid plexus papilloma
  • Choroid plexus carcinoma

Neuronal and mixed neuronal glial tumors

  • Dysembryoplastic neuroepithelial tumor
  • Gangliocytoma ganglioglioma
  • Anaplastic ganglioglioma
  • Dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease)
  • Desmoplastic infantile astrocytoma and ganglioglioma
  • Papillary glioneuronal tumor
  • Rosette forming glioneuronal tumor
  • Diffuse leptomeningeal glioneuronal tumor
  • Central neurocytoma
  • Extraventricular neurocytoma
  • Cerebellar liponeurocytoma
  • Paraganglioma

Tumors of the pineal region

  • Pineocytoma
  • Pineal parenchymal tumor of intermediate differentiation
  • Pineoblastoma
  • Papillary tumor of the pineal region

Embryonal tumors

  • Medulloblastoma, WNT activated
    • Medulloblastoma, SHH activated and TP53 mutant
    • Medulloblastoma, SHH activated and TP53 wildtype
    • Medulloblastoma, non WNT / non SHH
    • Medulloblastoma, group 3
    • Medulloblastoma, group 4
    • Medulloblastoma, classic
    • Medulloblastoma, desmoplastic / nodular
    • Medulloblastoma with extensive nodularity
    • Medulloblastoma, large cell / anaplastic
    • Medulloblastoma, NOS
  • Embryonal tumor with multilayered rosettes, C19MC altered
  • Embryonal tumor with multilayered rosettes, NOS
  • Medulloepithelioma
  • CNS neuroblastoma
  • CNS ganglioneuroblastoma
  • CNS embryonal tumor, NOS
  • Atypical teratoid rhabdoid tumor
  • CNS embryonal tumor with rhabdoid features

Tumors of the cranial and paraspinal nerves

  • Schwannoma
    • Cellular schwannoma
    • Plexiform schwannoma
    • Melanotic schwannoma
  • Neurofibroma
    • Atypical neurofibroma
    • Plexiform neurofibroma
  • Perineurioma
  • Hybrid nerve sheath tumor
  • Malignant peripheral nerve sheath tumor (MPNST)
  • Epithelioid MPNST
  • MPNST with perineurial differentiation

Meningiomas

  • Meningioma
    • Meningothelial meningioma
    • Fibrous meningioma
    • Transitional meningioma
    • Psammomatous meningioma
    • Angiomatous meningioma
    • Microcystic meningioma
    • Secretory meningioma
    • Lymphoplasmacyte rich meningioma
    • Metaplastic meningioma
    • Chordoid meningioma
    • Clear cell meningioma
  • Atypical meningioma
    • Papillary meningioma
    • Rhabdoid meningioma
  • Anaplastic (malignant) meningioma

Mesenchymal, nonmeningothelial tumors

  • Solitary fibrous tumor / hemangiopericytoma
  • Hemangioblastoma
  • Hemangioma
  • Epithelioid hemangioendothelioma
  • Angiosarcoma
  • Kaposi sarcoma
  • Ewing sarcoma / PNET
  • Lipoma angiolipoma
  • Hibernoma
  • Liposarcoma
  • Desmoid type fibromatosis
  • Myofibroblastoma
  • Inflammatory myofibroblastic tumor
  • Benign fibrous histiocytoma
  • Fibrosarcoma
  • Undifferentiated pleomorphic sarcoma / malignant fibrous histiocytoma
  • Leiomyoma
  • Leiomyosarcoma
  • Rhabdomyoma
  • Rhabdomyosarcoma
  • Chondroma
  • Chondrosarcoma
  • Osteoma
  • Osteochondroma
  • Osteosarcoma

Melanocytic tumors

  • Meningeal melanocytosis
  • Meningeal melanocytoma
  • Meningeal melanoma
  • Meningeal melanomatosis

Lymphomas

  • Diffuse large B cell lymphoma (DLBCL) of the CNS
  • Immunodeficiency associated
    • AIDS related DLBCL
    • EBV positive DLBCL
    • Lymphomatoid granulomatosis
  • Intravascular large B cell lymphoma
  • Low grade B cell lymphomas of the CNS
  • T cell and NK / T cell lymphomas of the CNS
  • Anaplastic large cell lymphoma, ALK positive
  • Anaplastic large cell lymphoma, ALK negative
  • MALT lymphoma of the dura

Histiocytic tumors

  • Langerhans cell histiocytosis
  • Erdheim-Chester disease
  • Rosai-Dorfman disease
  • Juvenile xanthogranuloma
  • Histiocytic sarcoma

Germ cell tumors

  • Germinoma
  • Embryonal carcinoma
  • Yolk sac tumor
  • Choriocarcinoma
  • Teratoma
    • Mature teratoma
    • Immature teratoma
  • Teratoma with malignant transformation
  • Mixed germ cell tumor

Tumors of the sellar region

  • Craniopharyngioma
    • Adamantinomatous craniopharyngioma
    • Papillary craniopharyngioma
  • Granular cell tumor of the sellar region
  • Pituicytoma
  • Spindle cell oncocytoma

Metastatic tumors

  • Lung
  • Kydney
  • Breast
  • Melanoma
  • Gastrointestinal
  • Bladder
  • Other

    Origin

    Author: Radiologist, Ph.D. Vlasov Evgeniy Alexandrovich

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