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. 2017 Feb 17:805–907.e1. doi: 10.1016/B978-0-323-35775-3.00014-X

Table 14-9.

Primary Tumors of the Nervous System

Cell of Origin Tumor Type Location Species Affected Gross Appearance
CNS
Embryonal cell Medulloblastoma Cerebellum (WM&GM) Dog, cow, cat, pig (young animals) Well-circumscribed, soft, gray to pink expansile mass (usually does not have hemorrhage, cysts, or necrosis).
Oligodendroglia Oligodendroglioma Cerebrum, brainstem, interventricular septum (WM&GM) Dog, cat, cow Well-demarcated, gray to pink-red, soft or gelatinous expansile mass, usually with areas of hemorrhage.
Astroglia Astrocytoma Pyriform lobe, cerebral hemispheres, thalamus-hypothalamus, midbrain, cerebellum, spinal cord (WM&GM) Dog, cat, cow Poorly demarcated, firm, gray-white when well differentiated; anaplastic neoplasms are moderately to well-demarcated, soft and friable (usually with areas of necrosis, hemorrhage, edema, and cavitation).
Ependyma Ependymoma Ventricular system (lateral; less commonly, third and fourth), central canal of the spinal cord Dog, cat, cow, horse Poorly to moderately to well-demarcated, soft and gray-white, invasive, destructive gelatinous expansile mass (usually with areas of hemorrhage and cavitation).
Choroid plexus epithelium Choroid plexus tumor Ventricular system (fourth; less commonly, third and lateral) Dog, horse, cow Well-demarcated, granular to papillary, gray-white to red, expansile mass.
Microglia Microgliomatosis Cerebrum, brainstem Dog Poorly demarcated, gray-white, infiltrative mass (may have perivascular pattern).
Endothelium Hemangiosarcoma Cerebrum, brainstem Dog Well-demarcated, invasive red to dark red, expansile mass.
Arachnoid cells Meningioma Meningeal surface of the CNS (convexity and lateral surfaces of the cerebral hemispheres, tentorium cerebelli, flax cerebri, ventral brainstem, spinal cord) Cat, dog, horse, cow, sheep Well-demarcated, variable shapes, firm, encapsulated, and gray-white to soft, red-brown or gray, expansile masses (usually with areas of hemorrhage and necrosis).
PNS
Schwann cells (other supportive cells) Peripheral nerve sheath tumor* Cranial nerves, spinal nerves (brachial plexus) Dog, cow, cat Firm or soft (gelatinous), white or gray, nodular masses.

CNS, Central nervous system; PNS, peripheral nervous system; WM&GM, white matter and gray matter.

*

Other names for this tumor type include schwannoma, neurofibroma, and neurilemmoma.