Types of brain tumor

Brain tumors are often classed as benign or malignant.

  • Benign brain tumors: These brain tumors are not as aggressive as malignant tumors. The mass or growth of abnormal cells does not contain cancer cells. Benign brain tumors grow slowly and tend not spread into other tissue.
  • Malignant brain tumors: This type of brain tumor does contain cancer cells and also tends not to have clear borders. These tumors are considered more dangerous as they grow rapidly and can invade other parts of the brain.

Doctors may also refer to a tumor based on where the tumor cells originated. If the tumor began in the brain, it can be referred to as a primary brain tumor. If it began in another part of the body and spread to the brain, it can be referred to as a secondary, or metastatic, brain tumor.

On May 9 2016, the World Health Organization officially reclassified all of the types of brain tumor. There are now over 120 types of brain tumors.

The American Brain Tumor Association (ABTA) estimate that there will be more than 79,000 new cases of primary brain tumors diagnosed in the United States in 2017. However, they have estimated that around one third of these will be malignant.

ABTA also estimate that there are currently around 700,000 people living with primary brain tumors in the U.S. According to ABTA, an estimated 16,700 people will die from brain and spinal cord tumors in 2017

Types of graft-versus-host disease

There are two types of GVHD: acute and chronic.

Acute GVHD

In some cases where stem cell transplant is used to treat cancer, GVHD may occur. This is the body reacting negatively to the new cells.

It is hard to say exactly how often acute GVHD occurs, but some reports say 20 percent others say even as high as 80 percent of people who undergo an allogenic transplant develop GVHD. This works out to over 5,500 people each year.

Acute GVHD is diagnosed within the first 100 days following an allogenic stem cell transplant, most commonly occurring within the first 2-3 weeks following the procedure.

During this time, the new bone marrow begins to make new blood cells and the donor’s immune cells start to attack the recipient’s healthy cells.

Acute GVHD can affect the skin, liver, and gut causing symptoms, such as skin rashes, diarrhea(sometimes with stomach pain and vomiting), or an increase in the liver enzymes. Some will go on to develop chronic GVHD.

Chronic GVHD

Chronic GVHD most commonly occurs in people who have experienced acute GVHD. It can occur anywhere from 3 months to more than a year following a stem cell transplant. Cases of chronic GVHD can range from mild to severe and can be long-lasting and debilitating.

What are Stem Cells?

Stem cells are a class of undifferentiated cells that are able to differentiate into specialized cell types. Commonly, stem cells come from two main sources:

  1. Embryos formed during the blastocyst phase of embryological development (embryonic stem cells) and
  2. Adult tissue (adult stem cells).

Both types are generally characterized by their potency, or potential to differentiate into different cell types (such as skin, muscle, bone, etc.).

Adult stem cells

Adult stem cells can divide or self-renew indefinitely, enabling them to generate a range of cell types from the originating organ or even regenerate the entire original organ. It is generally thought that adult stem cells are limited in their ability to differentiate based on their tissue of origin, but there is some evidence to suggest that they can differentiate to become other cell types.