POMS Reference

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DI 24585.001: Evaluation of Tumors of the Central Nervous System (tumors of the brain and spinal cord)

changes
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  • Effective Dates: 07/24/2015 - Present
  • Effective Dates: 05/01/2018 - Present
  • BASIC (04-10)
  • TN 1 (05-18)
  • DI 24585.001 Evaluation of Tumors of the Central Nervous System (tumors of the brain and spinal cord)
  • A. General
  • A. World Health Organization (WHO) classification system for establishing the grades of tumors of the brain and spinal cord
  • There are a number of classification systems that medical sources use to indicate the grades of tumors of the central nervous system. The World Health Organization (WHO) classification of tumors of the central nervous system (WHO Classification of Tumours of the Central Nervous System, 2007)1 is the most commonly used classification system. We consider a tumor of the central nervous system to be malignant if it is classified as grade II or higher under the WHO system (see 13.00K6 and 113.00K4). (See DI 34001.034 and DI 34005.113.)
  • There are several classification systems that medical sources use to identify the grades of tumors of the central nervous system (CNS). The WHO classification system is the one most commonly used in the United States when classifying tumors of the brain and spinal cord. WHO published a Fourth Edition of its classification system in 2007: WHO Classification of Tumours of the Central Nervous System.1 WHO revised the Fourth Edition in May 2016 to account for research into molecular and genetic markers of CNS tumors: WHO Classification of Tumours of the Central Nervous System, Revised.2 We consider a CNS tumor to be malignant if it is classified as grade II or higher in the WHO classification (see 13.00K6 and 113.00K4). (See DI 34001.034 and DI 34005.113.) CNS tumors not found in the 2007 version of the WHO classification system may instead be found in the 2016 version.
  • B. How to determine the WHO grade of a tumor of the central nervous system
  • B. The grades of tumors of the CNS in the 2007 version of the WHO classification system
  • If the medical evidence uses a classification system other than the WHO system, refer to the tables below to determine the tumor grade under the WHO system. If the tumor is WHO grade I, evaluate the tumor under the criteria in listings 11.05 and 111.05. (See DI 34001.030 and DI 34005.111.) If the tumor is WHO grade II, evaluate the tumor under listing 13.13A3 or 113.13C. If the tumor is grade III or IV under the WHO or another classification system, consider the tumor to be highly malignant and evaluate it under the criteria in listings 13.13A1 or 13.13A2 and 113.13A or 113.13B.
  • If the medical evidence uses a classification other than the WHO system, refer to the tables below from the 2007 version of the WHO system to help determine the tumor grade. If the tumor is WHO grade I, evaluate the tumor under the criteria in listings 11.05 and 111.05. (See DI 34001.030 and DI 34005.111.) If the tumor is WHO grade II, evaluate the tumor under listing 13.13A3 or 113.13C. If the tumor is grade III or IV in the WHO or another classification system, consider the tumor to be highly malignant and evaluate it under the criteria in listings 13.13A1 or 13.13A2 and 113.13A or 113.13B. The 2007 version of the WHO classification system is organized according to the cell type or anatomical structure of the CNS where the tumor originated.
  •   
  • Table A. WHO Grade I Tumors
  • Type of tumor
  • Name of tumor
  • Grade of tumor
  • Astrocytic tumors
  • Pilocytic astrocytoma2
  • Pilocytic astrocytoma3
  • I
  •  
  • Subependymal giant cell
  • I
  • Ependymal tumors
  • Myxopapillary ependymoma
  • I
  •  
  • Subependymoma
  • I
  • Choroid Plexus tumors
  • Choroid plexus papilloma
  • I
  • Other Neuroepithelial tumors
  • Angiocentric glioma
  • I
  • Neuronal and Mixed Neuronal-glial tumors
  • Desmoplastic infantile astrocytoma
  • I
  •  
  • Desmoplastic infantile ganglioglioma
  • I
  •  
  • Dysembryoplastic neuroepithelial tumor
  • I
  •  
  • Gangliocytoma
  • I
  •  
  • Papillary glioneuronal tumor
  • I
  •  
  • Paraganglioma of the spinal cord
  • I
  •  
  • Rosette-forming glioneuronal tumor of the fourth ventricle
  • I
  • Pineal tumors
  • Pineocytoma3
  • Pineocytoma4
  • I
  • Schwannomas
  • Cellular
  • I
  •  
  • Melanotic
  • I
  •  
  • Plexiform
  • I
  • Neurofibromas
  • Plexiform
  • I
  • Perineurioma
  • Intraneural perineurioma
  • I
  • Meningiomas4
  • Meningiomas5
  • Angiomatous
  • I
  •  
  • Fibrous (fibroblastic)
  • I
  •  
  • Lymphoplasmacyte-rich
  • I
  •  
  • Meningiothelial
  • I
  •  
  • Metaplastic
  • I
  •  
  • Microcystic
  • I
  •  
  • Psammomatous
  • I
  •  
  • Secretory
  • I
  •  
  • Transitional (mixed)
  • I
  • Mesenchymal
  • Angiolipoma
  • I
  •  
  • Chondroma
  • I
  •  
  • Epitheloid haemangioendothelioma
  • I
  •  
  • Haemangioma
  • I
  •  
  • Hibernoma
  • I
  •  
  • Leiomyoma
  • I
  •  
  • Lipoma
  • I
  •  
  • Osteochondroma
  • I
  •  
  • Osteoma
  • I
  •  
  • Rhabdomyoma
  • I
  •  
  • Solitary fibrous histocytoma
  • I
  • Melanomas
  • Diffuse melanocytosis
  • I
  •  
  • Melanocytoma
  • I
  • Other Tumors related to meninges
  • Haemangioblastoma
  • I
  • Teratomas
  • Mature teratoma
  • I
  • Tumors of the Sellar Region
  • Adamantinomatous craniopharyngioma
  • I
  •  
  • Craniopharyngioma
  • I
  •  
  • Granular cell tumor
  • I
  •  
  • Papillary craniopharyngioma
  • I
  •  
  • Pituicytoma
  • I
  •  
  • Spindle cell oncocytoma of the adenohypophysis
  • I
  •    
  • Table B. WHO Grade II Tumors
  • Type of tumor
  • Name of tumor
  • Grade of tumor
  • Astrocytic tumors
  • Diffuse astrocytoma
  • II
  •  
  • Fibrillary astrocytoma
  • II
  •  
  • Gemistocytic astrocytoma
  • II
  •  
  • Pilomyxoid astrocytoma
  • II
  •  
  • Pleomorphic xanthoastrocytoma
  • II
  •  
  • Protoplasmic astrocytoma
  • II
  • Oligodendroglial tumors
  • Oligodendroglioma
  • II
  • Oligoastrocytic tumors
  • Oligoastrocytoma
  • II
  • Ependymomas
  • Cellular
  • II
  •  
  • Clear Cell
  • II
  •  
  • Papillary
  • II
  •  
  • Tanycytic
  • II
  • Choroid Plexus tumors
  • Atypical choroid plexus papilloma
  • II
  • Other Neuroepithelial tumors
  • Chordoid glioma of the third ventricle
  • II
  • Neuronal and Mixed Neuronal-glial tumors
  • Central neurocytoma
  • II
  •  
  • Cerebellar liponeurocytoma
  • II
  •  
  • Extraventricular neurocytoma
  • II
  • Meningiomas
  • Atypical meningioma
  • II
  •  
  • Chordoid meningioma
  • II
  •  
  • Clear cell meningioma
  • II
  • Mesenchymal Tumors
  • Haemangiopericytoma
  • II
  •    
  • Table C. WHO Grade III Tumors
  • Type of tumor
  • Name of tumor
  • Grade of tumor
  • Astrocytic Tumors
  • Anaplastic astrocytoma5
  • Anaplastic astrocytoma6
  • III
  •  
  • Gliomatosis cerebri
  • III
  • Oligodendroglial Tumors
  • Anaplastic oligoastrocytoma
  • III
  •  
  • Anaplastic oligodendroglioma
  • III
  • Ependymal Tumors
  • Anaplastic ependymoma
  • III
  • Choroid Plexus Tumors
  • Choroid plexus carcinoma
  • III
  • Other Neuronal and Mixed Neuronal-Glial Tumors
  • Anaplastic ganglioma
  • III
  • Meningiomas
  • Anaplastic (malignant) meningioma
  • III
  •  
  • Papillary meningioma
  • III
  •  
  • Rhabdoid meningioma
  • III
  • Mesenchymal Tumors
  • Anaplastic haemangiopericytoma
  • III
  •    
  • Table D. WHO Grade IV Tumors
  • Type of tumor
  • Name of tumor
  • Grade of tumor
  • Astrocytic Tumors
  • Glioblastoma
  • IV
  • Tumors of the Pineal Region
  • Pineoblastoma
  • IV
  • Embryonal Tumors
  • Atypical teratoid/rhabdoid tumor
  • IV
  •  
  • Central nervous system Primitive neuroectodermal tumors (PNETs)
  • Central nervous system Primitive neuroectodermal tumors (PNETs)7
  • IV
  •  
  • Medulloblastoma6
  • Medulloblastoma8
  • IV
  • C. The grades of tumors of the CNS in the 2016 version of the WHO classification system
  • If the medical evidence uses a classification other than the WHO classification system or a tumor is not listed in the 2007 version of the WHO classification system, refer to the tables below from the 2016 version of the WHO classification system to help determine the tumor grade. If the tumor is WHO grade I, evaluate the tumor under the criteria in listings 11.05 and 111.05. (See DI 34001.030 and DI 34005.111.) If the tumor is WHO grade II, evaluate the tumor under listing 13.13A3 or 113.13C. If the tumor is grade III or IV under the WHO or another classification system, consider the tumor to be highly malignant and evaluate it under the criteria in listings 13.13A1 or 13.13A2 and 113.13A or 113.13B. As in the 2007 version, the 2016 version of the WHO classification system is organized according to the cell type or anatomical structure of the central nervous system where the tumor originated.9
  •   
  • Table E. WHO Grade I Tumors
  • Type of tumor
  • Name of tumor
  • Grade of tumor
  • Other Astrocytic tumors
  • Pilocytic astrocytoma10
  • I
  •  
  • Subependymal giant cell astrocytoma
  • I
  • Ependymal tumors
  • Myxopapillary ependymoma
  • I
  •  
  • Subependymoma
  • I
  • Other Gliomas
  • Angiocentric glioma
  • I
  • Choroid Plexus tumors
  • Choroid plexus papilloma
  • I
  • Neuronal and Mixed Neuronal-glial tumors
  • Desmoplastic infantile astrocytoma and ganglioglioma
  • I
  •  
  • Dysembryoplastic neuroepithelial tumor (DNET)
  • I
  •  
  • Dysplastic gangliocytoma of the cerebellum (Lhermitte-Ducios)
  • I
  •  
  • Gangliocytoma
  • I
  •  
  • Papillary glioneuronal tumor
  • I
  •  
  • Paraganglioma of the filum terminale
  • I
  •  
  • Rosette-forming glioneuronal tumor of the fourth ventricle
  • I
  • Tumors of the Pineal Region
  • Pineocytoma
  • I
  • Tumors of Cranial and Paraspinal Nerves
  • Cellular schwannoma
  • I
  •  
  • Melanotic schwannoma
  • I
  •  
  • Plexiform schwannoma
  • I
  •  
  • Plexiform neurofibroma
  • I
  •  
  • Atypical neurofibroma
  • I
  •  
  • Perineurioma
  • I
  •  
  • Epithelioid peripheral nerve sheath tumor
  • I
  • Tumors of Meningiomas Cells
  • Meningioma
  • I
  •  
  • Meningothelial meningioma
  • I
  •  
  • Fibrous meningioma
  • I
  •  
  • Microcystic meningioma
  • I
  •  
  • Angiomatous meningioma
  • I
  •  
  • Psammomatous meningioma
  • I
  •  
  • Secretory meningioma
  • I
  •  
  • Lymphoplasmacyte-rich meningioma
  • I
  •  
  • Metaplastic meningioma
  • I
  • Mesenchymal, Non-Meningothelial tumors
  • Angiolipoma
  • I
  •  
  • Chondroma
  • I
  •  
  • Desmoid-type fibromatosis
  • I
  •  
  • Haemangioblastoma
  • I
  •  
  • Hibernoma
  • I
  •  
  • Leiomyoma
  • I
  •  
  • Lipoma
  • I
  •  
  • Osteochondroma
  • I
  •  
  • Osteoma
  • I
  •  
  • Rhabdomyoma
  • I
  •  
  • Solitary fibrous tumor of the dura/haemangiopericytoma11
  • I
  • Melanocytic lesions
  • Meningeal melanocytosis
  • I
  •  
  • Meningeal melanocytoma
  • I
  • Teratomas
  • Mature teratoma
  • I
  • Tumors of the Sellar Region
  • Adamantinomatous craniopharyngioma
  • I
  •  
  • Adamantinomatous craniopharyngioma
  • I
  •  
  • Papillary craniopharyngioma
  • I
  •  
  • Granular cell tumor
  • I
  •  
  • Papillary craniopharyngioma
  • I
  •  
  • Pituicytoma
  • I
  •  
  • Spindle cell oncocytoma
  • I
  •    
  • Table F. WHO Grade II Tumors
  • Type of tumor
  • Name of tumor
  • Grade of tumor
  • Diffuse Astrocytic and Oligodendroglial tumors
  • Diffuse astrocytoma, IDH-mutant
  • II
  •  
  • Diffuse astrocytoma, IDH-mutant, gemistocytic
  • II
  •  
  • Diffuse astrocytoma, IDH-wildtype
  • II
  •  
  • Diffuse astrocytoma, not otherwise specified (NOS)
  • II
  •  
  • Oligoastrocytoma, not otherwise specified (NOS)
  • II
  •  
  • Oligodendroglioma, IDH-mutant, 1p19q co-deleted
  • II
  •  
  • Oligodendroglioma, not otherwise specified (NOS)
  • II
  • Other Astrocytic tumors
  • Pilomyxoid astrocytoma
  • II
  •  
  • Pleomorphic xanthoastrocytoma
  • II
  • Ependymal tumors
  • Papillary
  • II
  •  
  • Clear cell
  • II
  •  
  • Tanycytic
  • II
  •  
  • RELA fusion-positive
  • II
  • Other gliomas
  • Chordoid glioma of the third ventricle
  • II
  • Choroid Plexus tumors
  • Atypical choroid plexus papilloma
  • II
  • Neuronal and Mixed Neuronal-glial tumors
  • Central neurocytoma
  • II
  •  
  • Cerebellar liponeurocytoma
  • II
  •  
  • Extraventricular neurocytoma
  • II
  • Tumors of the Pineal Region
  • Pineal parenchymal tumor of intermediate differentiation12
  • II
  •  
  • Papillary tumor13
  • II
  • Tumors of the Cranial and Paraspinal Nerves
  • Epithelioid malignant peripheral nerve sheath tumor (MPNST)14
  • II
  •  
  • MPNST with perineural differentiation
  • II
  • Tumors of Meningothelial cells
  • Atypical meningioma
  • II
  •  
  • Chordoid meningioma
  • II
  •  
  • Clear cell meningioma
  • II
  • Mesenchymal, Non-Meningothelial tumors
  • Solitary fibrous tumor of the dura/haemangiopericytoma
  • II
  •    
  • Table G. WHO Grade III Tumors
  • Type of tumor
  • Name of tumor
  • Grade of tumor
  • Diffuse Astrocytic and Oligodendroglial tumors
  • Anaplastic astrocytoma, IDH-mutant15
  • III
  •  
  • Anaplastic astrocytoma, not otherwise specified (NOS)
  • III
  •  
  • Anaplastic oligoastrocytoma, not otherwise specified (NOS)
  • III
  •  
  • Anaplastic oligodendroglioma, IDH mutant, 1p19q co-deleted
  • III
  •  
  • Anaplastic oligodendroglioma, not otherwise specified (NOS)
  • III
  • Other Astrocytic tumors
  • Anaplastic pleomorphic xanthoastrocytoma
  • III
  • Ependymal tumors
  • Anaplastic ependymoma
  • III
  • Choroid Plexus tumors
  • Choroid plexus carcinoma
  • III
  • Neuronal and Mixed Neuronal-Glial tumors
  • Anaplastic ganglioglioma
  • III
  • Tumors of the Pineal Region
  • Pineal parenchymal tumor of intermediate differentiation
  • III
  •  
  • Papillary tumor of the pineal region
  • III
  • Tumors of the Cranial and Paraspinal Nerves
  • Epithelioid malignant nerve sheath tumor (MPNST)
  • III
  •  
  • MPNST with perineural differentiation
  • III
  • Tumors of Meningothelial Cells
  • Atypical meningioma
  • III
  •  
  • Papillary meningioma
  • III
  •  
  • Rhabdoid meningioma
  • III
  • Mesenchymal, Non-Meningothelial tumors
  • Epithelioid haemangioendothelioma
  • III
  •  
  • Angiosarcoma
  • III
  •  
  • Liposarcoma (intracranial)
  • III
  •  
  • Ewing sarcoma/ETMR
  • III
  •  
  • Fibrosarcoma
  • III
  •  
  • Kaposi sarcoma
  • III
  •  
  • Leiomyosarcoma
  • III
  •  
  • Undifferentiated pleomorphic sarcoma/malignant fibrous histiocytoma
  • III
  •  
  • Rhabdomyosarcoma
  • III
  •  
  • Solitary fibrous tumor of the dura/haemangiopericytoma
  • III
  •    
  • Table H. WHO Grade IV Tumors
  • Type of tumor
  • Name of tumor
  • Grade of tumor
  • Glioblastoma
  • Glioblastoma, IDH wildtype
  • IV
  •  
  • Giant cell glioblastoma, IDH wildtype
  • IV
  •  
  • Gliosarcoma, IDH wildtype
  • IV
  •  
  • Glioblastoma, IDH mutant
  • IV
  •  
  • Glioblastoma, not otherwise specified (NOS)
  • IV
  •  
  • Diffuse midline glioma, H3K27M-mutant
  • IV
  • Tumors of the Pineal Region
  • Pineoblastoma
  • IV
  • Embryonal tumors
  • Medulloblastoma, WNT-activated
  • IV
  •  
  • Medulloblastoma, SHH-activated & TP53-mutant
  • IV
  •  
  • Medulloblastoma, SHH-activated & TP53 wildtype
  • IV
  •  
  • Medulloblastoma, classic
  • IV
  •  
  • Medulloblastoma, desmoplastic/nodular
  • IV
  •  
  • Medulloblastoma, extensive nodularity
  • IV
  •  
  • Medulloblastoma, large cell/anaplastic
  • IV
  •  
  • Medulloblastoma, not otherwise specified (NOS)
  • IV
  •  
  • CNS neuroblastoma
  • IV
  •  
  • CNS ganglioneuroblastoma
  • IV
  •  
  • Embryonal tumor with multilayer rosettes (ETMR), C19MC-altered
  • IV
  •  
  • Embryonal tumor with multilayer rosettes (ETMR), not otherwise specified (NOS)
  • IV
  •  
  • Medulloepithelioma
  • IV
  •  
  • Atypical teratoid/rhabdoid tumor
  • IV
  •  
  • CNS embryonal tumor, not otherwise specified (NOS)
  • IV
  • Tumors of Cranial and Paraspinal Nerves
  • Epithelioid malignant nerve sheath tumor
  • IV
  •  
  • MPNST with perineural differentiation
  • IV
  • Footnotes:
  • [1]
  • Louis, D.N., Ohgaki, H., Cavenne, W.K. (eds), WHO Classification of Tumours of the Central Nervous System, IARC, Lyon, (2007).
  • Louis, D.N., Ohgaki, H., Wiestler, O.D., Ellison & Cavenne, W.K., editors, (2007) WHO Classification of Tumours of the Central Nervous System, Fourth Edition, Lyon: International Agency for Research Centre.
  • [2]
  • Includes juvenile pilocytic astrocytoma, a slower growing tumor that occurs mostly in children and young adults. The tumor forms in the brain more often than the spinal cord. (National Cancer Institute, http://www.cancer.gov/dictionary/ .)
  • Louis, D.N., Ohgaki, H., Wiestler, O.D. & Cavenne, W.K., editors, (2016) WHO Classification of Tumours of the Central Nervous System, Fourth Edition, Revised, Lyon: International Agency for Research Centre.
  • [3]
  • Some organizations and references, such as the National Cancer Institute, may classify pineocytoma as a grade II tumor. For the purposes of listings 13.13 and 113.13, we consider pineocytoma to be a WHO grade I tumor.
  • Includes juvenile pilocytic astrocytoma, a slower growing tumor that occurs mostly in children and young adults. The tumor forms in the brain more often than the spinal cord (see National Cancer Institute, http://www.cancer.gov/dictionary).
  • [4]
  • Most meningiomas are benign and approximately 80 percent are treated successfully with surgery. Meningiomas represent 13 percent to 27 percent of all intracranial tumors and are more common in females and older age groups. (Marosi, C. et al., Meningioma, Critical Reviews in Oncology/Hematology, Aug;67(2), 153-171 (2008).)
  • Some organizations and references, such as the National Cancer Institute, may classify pineocytoma as a grade II tumor. However, the WHO classification system lists pineocytoma as a grade I tumor. For the purposes of listings 13.13 and 113.13, we consider pineocytoma to be a grade I tumor.
  • [5]
  • WHO grade III anaplastic astrocytoma and grade IV glioblastoma multiforme include diffuse intrinsic brain stem gliomas, which are most common in children.
  • Most meningiomas are benign and approximately 80 percent are treated successfully with surgery. Meningiomas represent 13 percent to 27 percent of all intracranial tumors and are more common in females and older age groups (see Marosi, C., Hassler, M., Roessler, K., Reni, M., Sant, M. Massa, E. & Vecht, C., (2008). Meningioma, Critical Reviews in Oncology/Hematology, 67(2), 153-171, doi: 10.1016/j.critrevonc.2008.01.010; and also Di Muzio, B. & Gaillard, F. (2018). Meningioma, Radiopaedia, available online at https://radiopaedia.org/articles/meningioma).
  • [6]
  • Medulloblastoma is the most common brain tumor in childhood and one-third of these tumors occur during the first years of life. Adverse effects of radiation therapy in children include hearing loss, cognitive decline, endocrine abnormalities, and vascular complications. (Mueller, S. et al., Pediatric brain tumors: Current treatment strategies and future therapeutic approaches, Neurotherapeutics, Jul;6(7), 570-586 (2009).) Medulloblastomas and other primitive neuroectodermal tumors (PNETs) meet listing 13.13A2 or listing 113.13B if they have documented metastases.
  • WHO grade III anaplastic astrocytoma and grade IV glioblastoma multiforme in the 2007 version of the WHO classification system include diffuse intrinsic brain stem gliomas, which are most common in children. The 2016 version of the WHO classification system replaces the term “glioblastoma multiforme” with the term “glioblastoma and describes glioblastomas’ various subtypes.
  • [7]
  • The 2016 version of the WHO classification system does not use the term “primitive neuroectodermal tumor (PNET).” Instead, it lists these malignant tumors among the embryonal tumors. WHO made this change because molecular and genetic analysis of PNETs indicated this malignancy is comprised of two subtypes. These subtypes are “embryonal tumor with multilayer rosettes, C19MC-altered” and “embryonal tumor with multilayered rosettes, not otherwise specified (NOS)” (see Luijkx, T. & Jones, J. (2018). Primitive neuroectodermal tumour of the CNS, Radiopaedia, available online at https://radiopaedia.org/articles/primitive-neuroectodermal-tumour-of-the-cns).
  • [8]
  • Medulloblastomas are common in children, often occurring in early childhood. Adverse effects of radiation therapy for medulloblastomas include hearing loss, cognitive decline, endocrine abnormalities, and vascular complications (see Mueller, S. & Chang, S. (2009). Pediatric brain tumors: Current treatment strategies and future therapeutic approaches, Neurotherapeutics, 6(7), 570-586, doi: 10.1016/j.nurt.2009.04.006; and also Fortin, F. & Gaillard, F. (2018) Medulloblastoma, Radiopaedia, available online at https://radiopaedia.org/articles/medulloblastoma).
  • [9]
  • See Di Muzio, B. & Gaillard, F. (2018). WHO classification of CNS tumours, Radiopaedia, available online at https://radiopaedia.org/articles/who-classification-of-cns-tumours-1.
  • [10]
  • This benign tumor includes juvenile pilocytic astrocytoma, a slower growing tumor mostly in children and young adults. This tumor forms in the brain more often than the spinal cord (see National Cancer Institute, http://www.cancer.gov/dictionary). Juvenile pilocytic astrocytomas comprise 70-85 percent of all cerebellar astrocytomas (see Weerakkody, Y. & Gaillard, F., (2018). Pilocytic astrocytoma, Radiopaedia, available online at https://radiopaedia.org/articles/pilocytic-astrocytoma).
  • [11]
  • Solitary fibrous tumors of the dura/haemangiopericytoma can be grade I (benign), II, or III tumors.
  • [12]
  • Pineal parenchymal tumors of intermediate differentiation can be grade II or grade III tumors.
  • [13]
  • Papillary tumors of the pineal region can be grade II or grade III tumors.
  • [14]
  • Nerve sheath tumors can be grade II, III, or IV tumors.
  • [15]
  • WHO grade III anaplastic astrocytoma and grade IV glioblastoma include diffuse intrinsic brain stem gliomas, which are common in children.