Duhaime's Law Dictionary

Glioma Definition:

A species of brain tumor.

So-named as they arise from the glial cells in the brain.

This definition was adopted in a 2005 case:

"A glioma is a tumor arising from neuroglia. Neuroglia is supporting tissue that is intermingled with the essential elements of nervous tissue especially in the brain, spinal cord, and ganglia, is of ectodermal origin, and is composed of a network of fine fibrils and of flattened stellate cells with numerous radiating fibrillar processes.”1

The American Brain Tumor Association, circa 2013, proposes this plain language definition:

"Glioma is a general term used to identify any tumor that arises from the supportive (“gluey”) tissue of the brain.... This tissue, called glia, helps to keep the neurons in place and functioning well. The three main types of gliomas are: astrocytoma, oligodendromas, and ependymomas."

According to the Canadian Medical Association, and as of 1992, 60% of all brain tumors are gliomas.2 This is consistent with these words referred to by the British Columbia Workers' Compensation Appeal Tribunal in a 2008 case before it:

"... gliomas are by far the most common form of brain tumor, accounting for 60% of all cases diagnosed in the U.S. each year. ... (T)he cause of the condition is unknown."

In fact, glioma is often used synonymously with the term brain tumor.3

In US v. Catholic Healthcare West, Justice Fletcher of the United States Court of Appeals described gliomas as "malignant brain tumors".

Gliomas are distinguished according to a wide varierty of characteristics and categories such as low grade, mid-grade and other graded gliomas (eg. 2nd grade glioma or graded on a scale from I to IV), or in relation to their location (eg. optic nerve glioma, brain stem glioma, nasal glioma, left temporal lobe gloima). While all tend to grow and may therefore be described as malignant, most grow slowly.

A form of malignant glioma known as glioblastoma is described as follows:

"Glioblastomas are tumors that arise from astrocytes—the star-shaped cells that make up the “glue-like,” or supportive tissue of the brain. These tumors are usually highly malignant (cancerous) because the cells reproduce quickly and they are supported by a large network of blood vessels."4

Further, this from the Mayo Clinic circa 2013;

"Many different types of brain tumors exist. Some brain tumors are noncancerous (benign), and some brain tumors are cancerous (malignant)."5

The following medical evidence was led in one workplace legal action:

"(A) glioma (is a) central nervous system tumour commonly found in the brain.... A low-grade glioma ... can be stable for a very long period of time and show very little mass effect."6

One medical journal suggested that exposure to some chemicals may be related to a greater prevalence of gliomas especially exposure to arsenic, mercury, and petroleum products.7


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