EOD Primary Tumor


**Note 1:** The tentorium cerebelli is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes. The location of the tumor above or below the tentorium can help in determining the type of tumor; also most adult brain tumors are supratentorial, and most pediatric brain tumors are infratentorial. In the following list, note that ICD-O-3 codes C71.0 and C71.9 include both supratentorial and infratentorial subsites. - The following subsites are **Infratentorial** * All subsites for codes C716-C717 * Hypothalamus (C710) * Pallium (C710) * Posterior cranial fossa (C719) * Thalamus (C710) - The following subsites are **Supratentorial** * All subsites for codes C711-C715 * Primary site C710 (excluding hypothalamus, pallium, thalamus) * Anterior cranial fossa (C719) * Corpus callosum (C718) * Middle cranial fossa (C719) * Tapetum (C718) * Suprasellar (C719) **Note 2:** A midline shift is not the same thing as crossing the midline (code 500). * It must state tumor **crosses the midline** **Note 3:** Discontiguous spread, or "drop metastasis" are coded in EOD mets.
Code Description SS2018 T
050 Benign or borderline brain tumor B
100 Infratentorial tumor confined to - Brain stem or meninges of brain stem (one side) + Medulla oblongata + Midbrain (mesencephalon) + Pons - Cerebellum or meninges of cerebellum (one side or midline) + Lateral lobes + Median lobe of cerebellum + Vermis - Hypothalamus - Pallium - Thalamus Infratentorial tumor - Both cerebellum and brain stem involved with tumor on one side Supratentorial tumor confined to - Cerebral hemisphere (cerebrum) or meninges of cerebral hemisphere (one side) + Frontal lobe + Occipital lobe + Parietal lobe + Temporal lobe Confined to ventricles Tumor invades or encroaches upon ventricular system Confined to brain, NOS Confined to meninges, NOS L
500 Tumor crosses the midline Tumor invades - Bone (skull) (see code 700 for other bone involvement) - Contralateral hemisphere - Corpus callosum (including splenium) - Major blood vessel(s) - Meninges (e.g., dura) - Nerves (cranial, NOS) - Spinal cord/canal Supratentorial tumor extends infratentorially to involve - Brain stem - Cerebellum - Hypothalamus - Pallium - Posterior cranial fossa - Thalamus Infratentorial tumor extends supratentorially to involve - Anterior cranial fossa - Cerebrum (cerebral hemisphere) (excluding hypothalamus, pallium, thalamus) (See code 100 for hypothalamus, pallium, thalamus) - Middle cranial fossa - Suprasellar brain - Tapetum RE
700 Circulating cells in cerebral spinal fluid (CSF) Bone other than Skull (See code 500 for skull) Nasal cavity Nasopharynx Other direct extension outside CNS Posterior pharynx Further contiguous extension D
800 No evidence of primary tumor U
999 Unknown; extension not stated Primary tumor cannot be assessed Not documented in medical record Death Certificate Only U
(1) Fritz AG, Ries LAG (eds). **SEER Extent of Disease 1988: Codes and Coding Instructions (3rd Edition, 1998)**, National Cancer Institute, NIH Pub. No. 98-2313, Bethesda, MD, 1998 (2) Young JL Jr, Roffers SD, Ries LAG, Fritz AG, Hurlbut AA (eds.). **SEER Summary Staging Manual-2000: Codes and Coding Instructions**, National Cancer Institute, NIH Pub. No. 01-4969, Bethesda, MD, 2001. (3) Collaborative Stage Work Group of the American Joint Committee on Cancer. **Collaborative Stage Data Collection System User Documentation and Coding Instructions, version 02.05**. American Joint Committee on Cancer (Chicago, IL) (4) **Brain and Spinal Cord**, from the AJCC Cancer Staging System Version 9 (2022). Used with permission of the American College of Surgeons, Chicago, Illinois.