II.1.9.2 Determining Multiple Primaries For Brain and CNS Tumors

This page contains a discussion of determining the number of primaries. You can review this page in sequence or you can click one of the following links and jump directly to Site, Histology, Timing, or Laterality.

Site

Non-malignant CNS tumors are different primaries at the subsite level.

Examples

Meningioma of cervical spine dura (C70.1) and separate meningioma overlying the occipital lobe (C70.0, cerebral meninges). Count and abstract as 2 separate primary tumors.

The exception is when one of the primaries has an NOS site code (C__.9), and the other primary is a specific subsite within the same rubic. Meninges, NOS (C70.9) with spinal meninges (C70.1) or cerebral meninges (C70.0). Count as a single primary and code to the specific subsite.

Histology

Refer to the Histology Groups Table below, using the rules in priority order:

Histologic Group

ICD-O-3 Histology Code

Choroid plexus neoplasms

9390/0, 9390/1

Ependymomas

9383, 9394, 9444

Neuronal and neuronal-glial neoplasms

9384, 9412, 9413, 9442, 9505/1, 9506

Neurofibromas

9540/0, 9540/1, 9541, 9550, 9560/0

Neurinomatosis

9560/1

Neurothekeoma

9562

Neuroma

9570

Perineuroma, NOS

9571/0

  1. If all histologies are in the same histologic grouping or row in the table, then the histology is the same. Histologies that are in the same groupings are a progression, differentiation or subtype of a single histologic category.

Example

A subependymal giant cell astrocytoma (9384/1) of the cerebrum (C71.0) and a gliofibroma (9442/1) of the Island of Reil (C71.0), count as a single primary.*

  1. If the first 3 digits are the same as the first 3 digits of any histology in a grouping or row in the table above, then the histology is the same.
Example

A ganglioglioma (9505/1) of the cerebellum (C71.6) and a neurocytoma (9506/1) of the cerebellopontine angle (C71.6), count as a single primary.*

*Note: If one histology is an NOS and the other is more specific, code the specific histology. If both histologies are NOS or both are specific, code the histology that was diagnosed first.

  1. If the first 3 digits are the same but one or both histology codes are not found on the table above, then the histology is considered the same.
Example

Clear cell meningioma (9538/1) of the cerebral meninges and a separate transitional meningioma (9537/0) in another part of the same hemisphere, count as a single primary.

  1. If the histologies are listed in different groupings in the table, they are different histologies.
  2. If the first three digits of the histology code are different, and one or both histologies is not listed in the table above, the histology types are different. Report as two primaries.
Timing

If a non-malignant tumor of the same histology and same site as an earlier one is subsequently diagnosed at any time, it is considered to be the same primary.

Laterality

Beginning with malignant and benign/borderline CNS tumors diagnosed January 1, 2004 forward, the following sites require a laterality code of 1- 5 , or 9:

Laterality is used to determine if multiple non-malignant CNS tumors are counted as multiple primary tumors.

Counting Non-Malignant Primaries

B = Benign/borderline tumor

M = Malignant tumor

Counting Malignant Primaries

 

Same Histology *unless stated to be metastatic or recurrent

Tumor

Timing (months)

Same Site

Different Site

1st

Same Histology

Tumor

Timing (months)

Same Site

Different Site

1st

2nd

Same side

Other side

Unkn side

Same side

Other side

Unkn side

B

B

NA

1

2

1

2

2

2

B

M

< 2

2

2

2

2

2

2

B

M

2 +

2

2

2

2

2

2

Different Histology

Tumor

Timing (months)

Same Site

Different Site

1st

2nd

Same side

Other side

Unkn side

Same side

Other side

Unkn side

B

B

NA

2

2

2

2

2

2

B

M

< 2

2

2

2

2

2

2

B

M

2 +

2

2

2

2

2

2

2nd

Same side

Other side

Unkn side

Same side

Other side

Unkn side

M

M

< 2

1

1

1

2*

2*

2*

M

M

2 +

2*

2*

2*

2*

2*

2*

M

B

NA

2

2

2

2

2

2

Different Histology **unless one histology is a specific subtype of the other

Tumor

Timing (months)

Same Site

Different Site

1st

2nd

Same side

Other side

Unkn side

Same side

Other side

Unkn side

M

M

< 2

2**

2**

2**

2

2

2

M

M

2 +

2

2

2

2

2

2

M

B

NA

2

2

2

2

2

2

B = Benign/borderline tumor

M = Malignant tumor

 

 

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