PTCL is a group of aggressive (fast-growing) lymphomas that develop from mature T lymphocytes (T cells) and natural killer (NK) cells. The term ‘peripheral’ 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. In general, PTCL is more common in Asia and in the Caribbean.
PTCLs are classified into various subtypes, the four most common subtypes are:
|Peripheral T cell lymphoma, not otherwise specified (PTCL-NOS)
|Most common subtype of PTCL, refers to a group of aggressive (fast-growing) diseases that do not fit into any defined PTCL subtypes. It is more common in North America, and usually occurs in adults in their 50s and 60s. The disease will usually be confined to the lymph nodes, but can also involve sites such as the liver, bone marrow, gastrointestinal tract, and skin.
|Anaplastic large cell lymphoma (ALCL)
|Rare and aggressive (fast-growing) subtype. It is common in North America and Europe. It can occur at any age but is more common in children and young adults. ALCL can occur one of two ways, the first is cutaneously, meaning it starts in the skin and the lymphoma cells are only found in the skin (called ‘primary cutaneous ALCL’). Primary cutaneous ALCL is linked with a non-cancerous skin condition called lymphomatoid papulosis. The second way ALCL can occur is systemically, or throughout the body (called ‘primary systemic ALCL’). Primary systemic ALCL usually affects the lymph nodes, but it can also develop in organs or tissues other than the lymph nodes (lungs, liver, bone marrow, bones, skin, soft tissues). Patients with primary systemic ALCL are divided into two groups, depending on whether or not the surface of their cells express an abnormal form of the protein ALK. ALK-positive (expresses the protein) disease responds well to standard chemotherapy and patients tend to go into long-term remission. ALK-negative (does not express the protein) disease can initially respond to treatment, but patients tend to relapse within five years and require more aggressive treatment (stem-cell transplant).
|Angioimmunoblastic T cell lymphoma (AITL)
|Rare, aggressive (fast-growing) subtype. It is common in Europe, and usually occurs in middle-age to elderly people. Most people are diagnosed with advanced stage disease. Symptoms of AITL include high fever, night sweats, skin rash, and autoimmune disorders such as autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP). These autoimmune disorders cause the body to not recognise, and therefore destroy its own cells and tissues, such as red blood cells (in the case of AIHA) or platelets (in the case of ITP).
|Cutaneous T cell lymphomas (CTCLs)
|Group of T cell lymphomas, usually indolent (slow-growing), that originate in the skin. These lymphomas generally have a different prognosis and different treatment approaches (skin directed, radiation, systemically directed) than most T cell lymphomas. Mycosis fungoides is the most common type of cutaneous lymphoma that typically presents with red, scaly patches or thickened plaques of skin that often mimic eczema or chronic dermatitis. Progression from limited skin involvement is variable and may be accompanied by tumor formation, ulceration, and exfoliation, complicated by itching and infections. Advanced stages are defined by involvement of lymph nodes, peripheral blood, and internal organs.