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, including circulating cells in cerebrospinal fluid (CSF), is coded in EOD Mets.
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(4) Laws, E.R., Curran, W.J., et al. **Brain and Spinal Cord**. In: Amin, M.B., Edge, S.B., Greene, F.L., et al. (Eds.) AJCC Cancer Staging Manual. 8th Ed. New York: Springer; 2017