EOD

On this page...

Brain (EOD Primary Tumor)

Brain Schema
EOD Primary Tumor Comments
Benign/Borderline Tumor Applicable for Central Nervous System tumors only for years 2004+
  • Use code 8 when the behavior is /0 (benign) or /1 (borderline)
  • Size and extent of tumor is not relevant
This is coded strictly on behavior. Some benign/borderline tumors can get very large and push up against other structures; however, they are ALWAYS coded as benign/borderline.
In situ There is no in situ code for CNS tumors. In situ tumors do not occur in the CNS
Localized Tumors Before determining EOD Primary Tumor, you need to determine if your primary site is infratentorial or supratentorial. EOD Primary Tumor does provide some information on this, but this is also covered in this module (see CNS Anatomy and ICD-O-3 or Tentorium)

Localized includes:

  • Tumor confined to infratentorial sites
  • Tumor confined to supratentorial sites
  • Confined to brain (confined to CNS would be in the CNS Other schema)
  • Confined to meninges, NOS
Regional Tumors
  • Supratentorial tumor extending to an infratentorial site
  • Infratentorial tumor extending to a supratentorial site
  • Infratentorial or Supratentorial tumor extending to skull, contralateral hemisphere, corpus callosum, blood vessels, nerves, spinal cord, meninges

Regional tumors also include those tumors that cross the midline

  • These are tumors that start out on one side of the brain and directly extend to the other side of the brain (crossing the midline). Tumors that cross the midline have a worse prognosis than those that don’t
  • Note: A midline shift is not the same thing as crossing the midline.
    • A midline shift means that the tumor is pushing the midline away from the center, but the tumor itself has not extended over the midline
Distant Tumors Infratentorial vs Supratentorial is not relevant for distant tumors

Extension includes bone (other than skull), nasal cavity, nasopharynx, or other DIRECT extension outside the CNS

CNS Other (EOD Primary Tumor)

CNS Other
EOD Primary Tumor Comments
Benign/Borderline Tumor Applicable for Central Nervous System tumors only for years 2004+
  • Use code 8 when the behavior is /0 (benign) or /1 (borderline)
  • Size and extent of tumor is not relevant

This is coded strictly on behavior. Some benign/borderline tumors can get very large and push up against other structures; however, they are ALWAYS coded as benign/borderline.

In situ There is no in situ code for CNS tumors. In situ tumors do not occur in the CNS
Localized Tumors Confined to tissue or site origin
Regional Tumors Adjacent connective tissue
Adjacent organs
Distant Tumors Further contiguous extension

Intracranial Gland (EOD Primary Tumor)

Intracranial Gland
EOD Primary Tumor Comments
Benign/Borderline Tumor Applicable for Central Nervous System tumors only for years 2004+
  • Use code 8 when the behavior is /0 (benign) or /1 (borderline)
  • Size and extent of tumor is not relevant

This is coded strictly on behavior. Some benign/borderline tumors can get very large and push up against other structures; however, they are ALWAYS coded as benign/borderline.

In situ In situ
Localized Tumors Confined to tissue or site origin
Regional Tumors Adjacent connective tissue
Adjacent organs
Distant Tumors Further contiguous extension

EOD Regional Nodes (Applies to Brain, CNS Other, Intracranial Gland)

EOD Regional Nodes Comments
NA There are no regional lymph nodes for the CNS sites

EOD Mets (Applies to Brain, CNS Other, Intracranial Gland)

EOD Mets Comments
Benign/Borderline Tumor Benign/borderline tumors cannot be metastatic and are ALWAYS coded to no mets
Distant lymph nodes Although the CNS sites do not have regional lymph nodes, they can have distant lymph nodes
Metastatic sites
  • Extra-neural metastasis (metastasis outside of the CNS)
  • Drop Metastases: these are cells from the intracranial tumors that spread via the cerebrospinal fluid into the spine.
    • Leptomeningeal metastasis: also known as carcinomatous meningitis, and meningeal carcinomatosis, refers to the spread of malignant cells through the CSF.

Updated: September 23, 2026

Suggested Citation

SEER Training Modules: EOD. U.S. National Institutes of Health, National Cancer Institute. Cited 24 September 2026. Available from: https://training.seer.cancer.gov.