What is Peripheral T-cell Lymphoma?
Peripheral T-cell lymphoma (PTCL) is defined as a diverse group of aggressive lymphomas that develop from mature-stage white blood cells called T-cells and natural killer (NK) cells.
PTCL is classified as a type of non-Hodgkin’s lymphoma (NHL). NHL affects two particular types of white blood cells: B-cells and T-cells. PTCL specifically affects T-cells, and results when T-cells develop and grow abnormally.
It is PTCL’s origin in the lymphatic system that gave it the name peripheral T-cell lymphoma. In the case of PTCL, the term “peripheral” does not refer to the extremities, but identifies PTCL as a cancer that arises in the lymphoid tissues outside of the bone marrow such as lymph nodes, spleen, gastrointestinal tract, and skin. It is often not known why someone develops PTCL.
How common is PTCL?
PTCL currently represents 10 - 15 percent of all new NHL cases diagnosed each year and by some accounts, the number of cases being diagnosed is growing substantially. The growth in the incidence of PTCL may be driven by the aging population as well as by improvement in methods of diagnosis.
Subtypes of PTCL vary by geographic and ethnic groups
The term PTCL refers to a group of T- and NK-cell lymphomas that behave aggressively. There are several subtypes included in this group (see Figure 1 below). Subtypes may have different symptoms and clinical courses, and may require different diagnostic tests.
Experts have found that the overall incidence and frequency of these subtypes varies geographically.
PTCL in general is more common in Asia and the Caribbean. The most common subtype is called PTCL-not-otherwise specified (PTCL-NOS) and is most frequently diagnosed in individuals living in North America and Europe. Anaplastic large cell lymphoma (ALCL) is common in North America and Europe, whereas angioimmunoblastic T-cell lymphoma (AITL), the second most common subtype, is found more often in Europe. The types known as NK-/ T-cell lymphoma (NKTCL) and adult T-cell leukemia (ATLL) are most common in Asia.