An aggressive (fast-growing) type of non-Hodgkin lymphoma in which too many lymphoblasts (immature white blood cells) are found in the lymph nodes and the thymus gland. These lymphoblasts may spread to other places in the body. It is most common in teenagers and young adults and affects more males than females. It may be a T or B cell type. Also called precursor lymphoblastic lymphoma.
Last updated: 2016-01-06
Source: The National Cancer Institute's Dictionary of Cancer Terms (http://www.cancer.gov/dictionary)