Most of theALLs have –
Correct Answer: B - cell origin
Description: Ans. is 'a' i.e. B-cell origin Acute lvmphoblastic leukemia/lymphoma o Acute lymphoblastic leukemia (ALL) encompasses a group of neoplasms composed of immature, precursor B (Pre-B) or T (Pre-T) lymphocytes referred to as lymphoblast. o Majority (85%) of all ALLs are precursor B-cell tumors that typically manifest as childhood "Leukemia" with extensive bone marrow and variable peripheral blood involvement. o The less common precursor T-cell ALLs tend to present in adolescent males as "lymphomas", often with thymic involvement. o Peak incidence of Pre B-cell ALL is evident between 3-5 years and ALL is the most common childhood cancer. o Pre T-cell ALL occurs in adolescent male. o Morphology of tumor cell (lymphoblast). Having scant cytoplasm and nuclei somewhat larger than those of small lymphocytes. The nuclear chromatin is delicate and finely stippled and nucleoli are either absent or inconspicuous. Contain cytoplasmic aggregates of Periodic acid schiff (PAS)positive material. Clinical manifestations o Symptoms related to depression of normal marrow function. An accumulation of neoplastic blast cells in the bone marrow suppresses normal hematopoiesis by physical crowding and competition for growth factors. This results in : ? Anemia --> Fatigue, pallor Neutropenia --> Infection, fever Thrombocytopenia ---> Bleeding, petechiae, ecchymoses, epistaxis. These are the most common sign & symptoms. o Bone pain tenderness Resulting from marrow expansion and infiltration of the subperiosteum. o Generalized lymphodenopathy, Splenomegaly and hepatomegaly. Caused by neoplastic infiltration of these tissues. More common in ALL than AML. o Symptoms related to compression of large mediastinal vessels or airway. In Pre-T ALL of thymus. o CNS manifestation Due to meningeal involvement Headache, vomiting, nerve palsies. More common in ALL than in AML. o Testicular involvement is also more common inALL than in AML. Note o The FAB diagnostic criteria for acute leukemia is the presence of > 30 blasts in bone marrow (normal < 5%). o According to WHO classification, blasts should be > 20% in bone marrow for diagnosis of acute leukemia.
Category:
Pathology
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