T-lymphoblastic Leukemia (TLL)

T-lymphoblastic leukemia/lymphoma, previously labeled precursor T-lymphoblastic leukemia/lymphoma and also known as precursor T-cell lymphoblastic lymphoma and precursor T acute lymphoblastic leukemia/lymphoma is a form of lymphoid leukemia and lymphoma in which too many T-cell lymphoblasts are found in the blood, bone marrow, and tissues, particularly mediastinal lymph nodes. Labeling as leukemia or lymphoma depends on which feature is more pronounced in a given situation, but has no biological or treatment implication. It is uncommon in adults, but represents 15% of childhood acute lymphoblastic leukemia and 90% of lymphoblastic lymphoma.