Clinical Definition

Lymphoma is a cancer of the lymph system that occurs when white blood cells, known as lymphocytes, become abnormal.

In Our Own Words

Lymphoma is the most common type of blood cancer. However, there are many different types of lymphoma and they fall into two main categories: Hodgkin lymphoma or non-Hodgkin lymphoma (NHL). Lymphomas occur when cells known as lymphocytes begin dividing faster than they are supposed to, or living longer than they should. Because the lymph system runs throughout the body, lymphoma can develop in different regions, including the lymph nodes (neck, groin), the spleen or other vital organs.

Non-Hodgkin lymphoma can actually be broken down into scores of different types—so much so that the classification of NHL can be confusing even to doctors.  While some types of NHL are important in pediatrics, about 95 percent of NHL cases occur in adults.