T-cell lymphoma is a type of cancer that originates in the T-cells, which are a crucial part of the immune system. These cells help the body fight infections and diseases. When T-cells become cancerous, they can grow uncontrollably, leading to various symptoms such as swollen lymph nodes, fever, and weight loss. There are several subtypes of T-cell lymphoma, each with different characteristics and treatment options. Diagnosis typically involves blood tests, imaging studies, and a biopsy of affected tissue. Treatment may include chemotherapy, radiation therapy, or targeted therapies, depending on the specific type and stage of the disease.