There are many types of lymphoma, all classified based on their cell type, cell markers, location of the cancerous mutation, and how they grow. However, the classification systems have changed and evolved over the years as scientists and doctors learn more about the disease.
The different systems used are the Rappaport System, Kiel System, Working Formulation, Revised European-American Classification of Lymphoid Neoplasms (REAL), and the World Health Organization (WHO) Sytem.
The WHO International Classification of Diseases was first published 1893. The ICD is the international standard diagnostic classification and we regard it as the best current model. Please visit our Lymphoma Classification page for more details.
The Rappaport System
This system was used until the mid 1970's. The classification system divides cells into three categories based on cell differentiation. Cell differentiation is the process in which immature cells become specialized, mature cells. The categories were:
- Well differentiated cells, or small lymphocytic lymphoma
- Poorly differentiated cells, or follicular and small cleaved lymphomas
- Histiocytic cells, or large cell lymphomas
- It was created prior to the distinction between B-cells and T-cells, and is now rarely used. The only way to tell the cell types apart was by looking under a microscope, and the updated tissue tests available nowadays can categorize cancerous cells much better.
The Kiel System
The Kiel System was popular in Europe and was introduced in 1974. It was based on immunologic tests that identified the proteins that cancer cells made. In the United States, a similar system, called the Lukes and Collins Classification, was the first to classify based on B-cell and T-cell types.
National Cancer Institute's Working Formulation (IWF)
This system was introduced in the 1980's and classified cells based on cell differentiation, cell size, and whether or not the cell was cleaved. This led to the distinction between low-grade and high-grade cancers.
Small lymphocytic lymphoma, follicular small-cleaved cell lymphoma, and follicular mixed small-cleaved and large cell lymphomas were all considered low grade.
Diffuse small cleaved cell, diffuse mixed small and large cell, diffuse large cell, and follicular large cell lymphoma were all considered intermediate grade.
Lymphoblastic, small non-cleaved cell, and large cell immunoblastic lymphomas were all considered high grade.
These classification systems were revised in the 1990's by the International Lymphoma Study Group. They compiled a consensus of lymphomas in order to study and classify them. This system became the basis of the WHO system in place today.