Solid Tumor Manual – Malignant CNS and Peripheral Nerves Overview


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As of 1/22/2019 the following is an excerpt from the Solid Tumor Manual.  Please review the manual for complete instructions and details.

C470-479, C700, C701, C709, C710-C719, C720-C725, 728, C729, C751-C753

  • Non-Malignant intracranial and CNS tumors are NOT included.  They have a separate set of rules.
  • The 2007 rules said a glioblastoma multiforme (GBM) following an astrocytic or glial tumor was a single primary.  In the 2018 Solid Tumor Rules GBM subsequent to an astrocytic or glial tumor is a multiple primary. GBM is now being collected as a new primary so it is possible to analyze the frequency with which these tumors recur in a more aggressive form (GBM).
  • The following meningiomas are reportable:
    • Intraosseous
    • Cavernous sinus
    • Sphenoid wing
  • Multiple cerebral meningiomas are a single primary
  • Multiple brain tumors of same histology are single primary
  • Laterality is not used to determine multiple primaries
  • Timing is not used to determine multiple primaries
  • The brain C710-C719 is a single primary site
  • Neurofibromatosis NOS, Neurofibromatosis 1 (NF1), Neurofibromatosis 2 (NF2), and schwannomatosis are genetic syndromes and not reportable neoplasms.  People with this genetic syndrome do have a high risk of developing:
    • Non-reportable non-malignant tumors occurring in skin and sites other than CNS AND
    • Reportable malignant tumors

The 2016 WHO (World Health Organization) Classification of Tumors of the Central Nervous System contains newly recognized histologies and subtypes/variants.  New codes/terms are identified by asterisks (*) in Table 3 in Terms and Definitions

  • CNS neoplasms must meet all three of the conditions below to be reported as malignant /3

1.The behavior must be malignant /3

    • The tumor is a WHO Grade 3 or 4 (See Section 1: Table 1
      • Note that WHO Grade 2 tumors may be non-malignant or malignant
      • Always code the behavior as designated by the pathologist
      • Never report a malignant /3 behavior code for a meningioma based on tumor extension to brain, skin of scalp, or other regional organs/tissue.  Non-malignant CNS tumors can extend to the regional tissue and bone

2.The primary site must be reportable (See Section 2: Table 2) AND

3.The histology must be reportable (See Section 2: Table 3)

Behavior determines which set of CNS rules should be used: malignant vs non malignant.

Priority Order for Using Documentation to Assign Behavior:  Start with Instruction 1 and STOP when you reach the instruction that applies to the case being abstracted:

1. Pathology: Tissue from resection

  • Use pathologist’s description of malignant/invasive behavior
  • Cases are reportable as malignant when pathology states WHO Grade 3 or 4
  • WHO Grade 2 may be either non-malignant or malignant.  Use the pathologist’s description of behavior
  • Never change behavior described by pathologist

2.Pathology:  Tissue from biopsy

3.Cytology (usually cerebrospinal fluid)

4.Physician’s documentation (no pathology report) in the following priority order

  • Tumor Board
  • Documentation of original pathologic diagnosis and behavior
  • Documentation of behavior, no mention of original diagnosis

5.Scan, use behavior information from radiography in the following priority order

  • MRI
  • CT
  • PET
  • Angiogram

When instructions 1-5 do not apply use Table 1 to determine behavior

After determining behavior code, the next step is to confirm both the primary and the histology are reportable:

  • All malignant tumors are reportable including peripheral nerve tumors AND
  • The Malignant CNS and Peripheral Nerve rules contain the correct histologies and coding rules for tumors of peripheral nerves and meninges/dura
  • Peripheral nerves are extracranial or extradural
  • The following malignant meningiomas are reportable:
    • Intraosseous.  The primary site for intraosseous meningioma is cranial meninges C700
    • Sphenoid Wing.  Sphenoid wing meningiomas arise in the cranial meninges C700 which covers the bony structure called the sphenoid wing
    • Cavernous sinus. There is no ICD-O site code for cavernous sinus because tumors do not arise in the sinus itself; the primary sites are:
      • The cranial nerves passing through the sinus (trochlear, abducent C725) OR
      • The cerebral meninges/dura C700 covering the cranial nerve

The classification of brain tumors is a subjective matter because definitive criteria have not been established/accepted. Pathologist may disagree on the histology or behavior. Follow the steps below for coding the histology and/or behavior of tumor when there are discrepancies:

  • When possible, get advice from the pathologist
  • When possible, contact attending physician
  • When possible, consult with registry advisor
  • If none of these options are available, code the histology and behavior from the most dependable source (see Priority List for Coding Histology)

Use Table 5 to identify sites for which laterality must be coded.  Do NOT use this table to determine multiple primaries:

Paired Sites and Codes:

  • Acoustic Nerve C724
  • Cerebral Meninges C700               
  • Cerebrum C710
  • Cranial Nerves C725
  • Frontal Lobe C711
  • Occipital Lobe C714
  • Olfactory Nerve C722
  • Optic Nerve C723
  • Parietal Lobe C713
  • Temporal Lobe C712

Midline tumors are common for glioblastoma multiforme and meningiomas

Code the most specific histology when any one of the following criteria are met:

1.Code the histology when the exact term is documented

2.Code the histology when described as:

    • Subtype
    • Type
    • Variant
    • Note: The most specific histology may be described as component, majority/majority of, or predominantly

3.Code the histology described as differentiation or features/features of ONLY when there is a specific ICD-O code for the “NOS with ____ features” or “NOS with ____ differentiation”

    • Note: Do not code differentiation or features when there is no specific ICD-O code

4.Code the histology described by ambiguous terminology ONLY when:

    • Histology is clinically confirmed by a physician (attending, pathologist, oncologist, etc)
    • Patient is receiving treatment based on the histology described by an ambiguous term
    • Case is accessioned based on ambiguous terminology and no other histology information is available/documented

Do Not Code histology when described as:

  • Architecture
  • Foci, focus, focal
  • Pattern
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