T-cell lymphoma

There are many types and variations of T-cell lymphoma, each with vastly different symptoms, survival, and prognosis. The classification of T-cell lymphoma has been difficult to accomplish due to the lack of understanding of their biology. Common • Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS): Most common type of Peripheral T-cell lymphoma (PTCL), comprising subtypes which cannot be classified as either nodal, extra-nodal, or leukemic • Angioimmunoblastic T-cell lymphoma (AITL): Aggressive form of T-cell lymphoma. • Anaplastic large cell lymphoma (ALCL): ALCL has four distinct types: • ALK-positive anaplastic large cell lymphoma: an aggressive, systemic ALCL that strongly expresses anaplastic lymphoma kinase, i.e. ALK. • ALK-negative anaplastic large cell lymphoma: an aggressive, systemic ALCL that does not express ALK. • Primary cutaneous anaplastic large cell lymphoma: a less aggressive ALCL that commonly presents as skin tumors. • Breast cancer-associated anaplastic large cell lymphoma: a less aggressive ALCL that occurs around and is caused by breast implants. • Adult T-cell leukemia/lymphoma (ATL): Aggressive T-cell lymphoma, associated with RNA retrovirus, human T-cell leukemia virus type-1 (HTLV1) • Extranodal NK/T-cell lymphoma, nasal type (ENKTL): Aggressive T-cell lymphoma, usually associated with Epstein–Barr virus (EBV) • Cutaneous T-cell lymphoma (CTCL): can be indolent or aggressive • Mycosis fungoides • Sézary syndrome Rare • Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) • Cutaneous gamma-delta T-cell lymphoma (CGD-TCL) • Systemic Epstein–Barr virus-positive T-cell Lymphoproliferative Disorders of Childhood (EBVTCLD): A very aggressive group with association with Epstein–Barr virus (EBV) • Primary intestinal T-cell lymphomas • Enteropathy-associated T-cell lymphoma (EATL) • Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL). • Hepatosplenic T-cell lymphoma (HSTCL) ==Symptoms and signs==

include Differences in T-cell lymphoma subtypes extend to the clinical characteristics and symptoms of the disease with each varying drastically. As a result, there is almost no universally known symptom that can be applied to all T-cell lymphoma subtypes. The hemophagocytic syndrome (HPS) Hemophagocytic syndrome has been associated with most T-cell lymphoma subtypes, and is commonly characterized by fevers, reduction of lymphocytes numbers, enlarged liver or spleen, and liver dysfunction. These symptoms are especially common in extranodal T-cell lymphoma subtypes which develop outside the lymph nodes, such as extranodal NK/T-cell lymphoma, nasal type, and cutaneous T-cell lymphoma (CTCL). Swollen lymph nodes T-cell lymphoma which develops from the lymph nodes commonly causes symptoms as such swollen lymph nodes. The swelling normally will not cause any pain and can be felt or seen as lumps on the surface of the skin. Nodal T-cell lymphoma subtypes such as peripheral T-cell lymphoma will often develop this symptom. Skin infections T-cell lymphoma can cause eczema or rash-like symptoms where small red patches will appear around the skin. These patches will often be irritated and may appear slightly lighter in colour compared to the rest of the skin. Occasionally, small lumps will develop which may rupture and cause the surface layer of the skin to break open. This is especially common in Cutaneous T-cell lymphoma subtypes. ==Cause==

There is no definitive cause for most T-cell lymphoma subtypes, but a variety of risk factors have been linked to an increased likelihood of developing the disease. ==Risk factors==

A family history of hematopoietic malignancies has been linked to an increased association with most T-cell lymphoma subtypes. This link is especially elevated among individuals 50 years or younger. More than 90% of individuals are exposed to the Epstein–Barr virus in their lifetime. EBV has been consistently associated with many lymphoproliferation disorders, of these EBV-associated T-cell lymphomas include Epstein–Barr virus–associated lymphoproliferative diseases, angioimmunoblastic T-cell lymphoma (AITL), extranodal NK/T-cell lymphoma, nasal type, and peripheral T-cell lymphoma not otherwise specified (PTCL, NOS). The human T-cell leukemia virus-1 is endemic in regions such as Japan and the Caribbean and has been associated with the increased risk of T-cell lymphoma such as Adult T-cell leukemia/lymphoma (ATL). HTLV-1 has been attributed to 56% and 78% of all ATL cases in Japan and the Caribbean respectively. ==Diagnosis==

The diagnosis of T-cell lymphoma varies largely between the subtypes. Some subtypes like anaplastic large-cell lymphoma have an exceptional diagnostic rate however, for a majority of T-cell lymphoma subtypes the diagnosis is often flawed due to the difficulty to culture damaged lymphoma cells and the overall low frequency of cases compared to other Non-Hodgkin lymphoma. The current and most accurate diagnosis used across most subtypes is a biopsy in which fresh tissue that is suspected to be affected by the lymphoma is collected from the patient to be closely examined by pathology laboratories. Other diagnostic methods are specific to the type of T-cell lymphoma, physical examination of skin or lymph nodes is common for cutaneous subtypes of T-cell lymphoma whilst others may be diagnosed using blood tests. Series of scans such as CT scan, MRI, ultrasounds, and even X-rays may also be used for diagnostic purposes. ==Treatment==

Treatment for T-cell lymphoma varies widely due to the large variability in the subtypes. Due to the lack of research performed in understanding the nature of T-cell lymphoma pathogenesis, a majority of cases will often have poor outcomes for the treatment or will relapse. Monoclonal antibodies can be used as a single treatment agent, however, are more effective when used concurrently with chemotherapy to improve survival and remission. Commonly used monoclonal antibody used to treat T-cell lymphoma include alemtuzumab and denileukin difititox. Nucleoside analogs Nucleoside analogs are a type of antiviral cytotoxic drug used to treat various cancer related diseases. It possesses highly immunosuppressive abilities and acts by inhibiting viral replication and prevent the spread of the cancerous growth. Nucleoside analogs are one of the most active class of drug used to treat T-cell lymphoma. Other Other non-traditional treatment options include targeted therapy, protease inhibitors, signaling inhibitors, and HDAC inhibitors. ==Epidemiology==

While the incidence of Non-Hodgkin's lymphoma has plateaued, the rate of T-cell lymphomas has gradually increased over the past few years. However, due to the low frequency and lack of research performed on the disease, the number of cases is relatively underrepresented in comparison to other non-Hodgkin lymphomas. with cases increasing in frequency with age for most subtypes. In Asia, T/NK-cell neoplasms are more common as a result of host factors and the higher prevalence of human T-cell leukemia virus-1 (HTLV1) and Epstein–Barr virus (EBV). While enteropathy-associated T-cell lymphoma (EATCL) is more common among Irish and Welsh populations. ==See also==