What Is Lymphoma? Hodgkin & Non-Hodgkin Lymphoma, Explained

Medically Reviewed by Dr. Samantha Miller, MBChB

Photo Courtesy: Westend61/Getty Images

Lymphoma is a type of blood cancer that affects cells of the immune and lymphatic systems, known as lymphocytes. Lymphocytes are white blood cells that are key in defending against foreign pathogens. Lymphocytes are broken down into two major subgroups: B lymphocytes and T lymphocytes, which are commonly referred to as B cells and T cells respectively. 

To this end, lymphoma occurs when there is a malignant transformation of either the B or T cells, and they grow rapidly and uncontrollably. The Leukemia and Lymphoma Society estimates that there are just under 800,000 people living with, or in remission from, lymphoma in the United States.

Subtypes of Lymphoma

There are two main types of lymphoma:

  • Hodgkin lymphoma (HL)
  • Non-Hodgkin lymphoma (NHL)

Hodgkin lymphoma, also known as Hodgkin disease, is named after Thomas Hodgkin and is characterized by the presence of an abnormal cell called a Reed-Sternberg cell, seen under the microscope. Reed-Sternberg cells typically originate from B lymphocytes and are quite large in size when compared to other cells. The main difference in classification that helps a physician make a diagnosis of NHL is the absence of Reed-Sternberg cells.

Hodgkin lymphoma is less prevalent than NHL, and typically occurs in individuals between the ages of 15 and 40, or anyone who is 55 or older. NHL is one of the most common forms of cancer among men and women, and can be split into multiple subgroups depending upon the appearance and characterization of the malignant lymphocytes.