Human T Cell Leukemia Lymphomas, also referred to as HTLV-1-associated leukemias or lymphomas, are a type of cancer that affects the white blood cells in the body. These diseases are caused by the Human T-cell Lymphotropic Virus type 1 (HTLV-1) and typically develop slowly over many years. Synonyms for Human T Cell Leukemia Lymphomas include HTLV-1-associated leukemia and lymphoma, adult T-cell leukemia, and HTLV-1-associated myelopathy/tropical spastic paraparesis. These terms are used interchangeably to describe the various manifestations of this disease. It is important to raise awareness about these synonyms to ensure accurate understanding and communication within the medical community and among patients and their families.