B AND T LYMPHOBLASTIC LYMPHOMA/LEUKEMIA
Karyotypic abnormalities: Most pre-B-cell tumors are hyperdiploid. Translo-cations are common in both B-ALL and T-ALL.
Immunophenotyping. Most tumors are positive for terminal deoxytransferase (TdT).
• B-cell lineage classification is based on presence or absence of cytoplas-mic or surface markers, including surface immunoglobulin (sIg) pres-ence (mature B-ALL) and cytoplasmic μ presence (pre-BALL). The B-cell tumors almost always express B-cell molecules CD19 and CD10.
• T-cell lineage: The majority of T-ALLs stain with CD2, CD3, CD5, and CD7.
B-ALL is more common in children; symptoms include fever, anemia, and bleeding
T-ALL often presents as a mediastinal mass in an adolescent male
Most cases of lymphoblastic lymphoma are T-cell neoplasms that are aggressive and rapidly progressive. Most patients are young males with a mediastinal mass (think thymus). The leukemic phase of lymphoblastic lymphoma is similar to T-ALL and some consider them the same entity. Most cells are CD1+, CD2+, CD5+, and CD7+.