A disease of lymphocytes called T-lymphocytes, or "T-cells" that are found most commonly in the skin, spleen, blood, bone marrow, and/or lymph nodes. Peripheral T-cell lymphoma (PTCL) and cutaneous T-cell lymphoma (CTCL) are the two main types of T-cell lymphoma; however, there are many different subtypes of PTCL and CTCL and all are very rare.
The exact cause of T-cell lymphomas is not known, but certain viral infections such as the Epstein-Barr Virus (EBV) and human T-cell leukemia virus have been associated with development of T-cell lymphomas. The stage of T-cell lymphoma can vary at diagnosis and throughout treatment. Stages of T-cell lymphoma include stage I, II, III, and IV. The effectiveness of the treatment may depend upon the stage and specific subtype at diagnosis.