Lymphoma Types

Categorization and definition of lymphoma types has changed a great deal during the last decade. Back in the 1970s, physicians used multiple classification guidelines. No “gold standard” existed and, inevitably, this gave rise to much controversy among members of the medical profession.

Attempts to standardize the various methods of classification were introduced almost thirty years later. The International Lymphoma Study Group (ILSG) produced a consensus list of variations of lymphoid cancer. The Group’s findings were published in 1994 under the title Revised European-American Classification of Lymphoid Neoplasms (REAL).

In 1995, the European Association of Pathologists (EAHP) and the Society for Hematopathology (SH) started work on a revised classification system. The outcome is the recently published new World Health Organization (WHO) Classification, based upon an updated version of the REAL classification system.

What’s New?

Today’s internationally accepted classification system uses the term “entities” to distinguish the many “real” lymphoma types. For example, a cancer of the lymph nodes that was previously labeled as a straightforward low or high-grade tumor is now viewed as a specific entity. This means that individual cancers can be treated in the most appropriate manner for the specific type of malignancy.

The new, detailed categorization system has given a tremendous boost to diagnostic efficiency and has led, ultimately, to improved prognosis. In addition, there has never been a more optimistic or better time for people with the condition to take part in clinical trials and become part of the latest research.

The WHO Classification

The WHO classification system is currently accepted as the authoritative standard for the diagnosis of lymphomas. WHO does not group lymphomas into prognostic categories, but, rather, considers each lymphoma as a separate disease.

The WHO system uses morphology (the appearance of the cell under the microscope), immunophenotyping (an analysis of the proteins on the surface of the lymph node cell) and genotyping (genetic analysis) to narrow down the type of malignant tumor involved. In addition, as with other forms of cancer, the malignancies may be graded, typically from I to IV.

Categorization: An Overview

Lymphomas are classified into two broad categories: Hodgkin’s disease and non-Hodgkin’s lymphoma, with NHL nearly ten times as common as HD.

The Four Main Categories of Hodgkin’s Disease

HD is categorized into four main types, based on the tumors’ histology (appearance under the microscope). The presence of the Reed-Sternberg (RS) cell is common to all four types.

The four main types are:

  • Nodular Sclerosis: the most common form of HD (moderately aggressive)
  • Mixed Cellularity: the next most common form of HD (moderately aggressive)
  • Lymphocyte Depleted: a relatively uncommon form of HD (aggressive)
  • Lymphocyte Predominant: the least common form of HD (least aggressive).

Categories of NHL Types

Thanks to the recent introduction of the World Health Organization (WHO) categorization method, the complex and various non-Hodgkin’s types can now be diagnosed with a high degree of accuracy. The following list offers but a few examples of the many NHL types and subtypes, according to the latest WHO classification system:

  • small lymphocytic
  • follicular
  • mantle cell
  • MALT
  • diffuse large cell B-cell
  • mediastinal large B-cell
  • precursor T lymphoblastic
  • cutaneous T-cell
  • T-cell and natural killer cell
  • mature (peripheral) T-cell
  • Burkitt’s lymphoma
  • mycosis fungoides
  • Szary Syndrome.

Resources

ClinicalTrials.gov. (2001). Ganciclovir plus Arginine Butyrate in treating patients with cancer or lymphoproliferative disorders associated with the Epstein Barr virus. Retrieved April 14, 2003, from www.clinicaltrials.gov/ct/gui/show/NCT00006340?order=27.

Coiffier, B. (2003). Monoclonal antibodies combined to chemotherapy for the treatment of patients with lymphoma. Blood Reviews, 17, 25-31.

Harris, N. L., Jaffe, E. S., Diebold, J., Flandrin, G., Muller-Hermelink, H.K., Vardiman, J. (2000). Lymphoma classification from controversy to consensus: the R.E.A.L. and WHO Classification of lymphoid neoplasms. Annals of Oncology, 11(Suppl 1), 3-10.

Lymphoma Information Network. (2000). Adult non-Hodgkin’s lymphoma. Retrieved April 14, 2003, from www.lymphomainfo.net/nhl/description.html.

Lymphoma Information Network. (2000). Lymphoma classification and typing. Retrieved April 14, 2003, from www.lymphomainfo.net/nhl/classify.html.

Lymphoma Research Foundation. (2002). How is non-Hodgkin’s lymphoma classified and graded? Retrieved April 14, 2003, from www.lymphoma.org/site/PageServer?JServSessionIdr010=spjnfiziow .app1a