hematology and oncology
Acute Lymphoblastic Leukemia (ALL)
Diagnosis of ALL
Complete blood count (CBC) and peripheral blood smear Bone marrow examination Histochemical studies, cytogenetics, and immunophenotyping A diagnosis of acute lymphoblastic leukemia is made when blast cells of lymphoid origin are ≥ 20% of marrow nucleated cells or ≥ 20% of non-erythroid cells when the erythroid component is > 50%. If marrow cells are insufficient or unavailable, diagnosis can be made by the same criteria using a peripheral blood sample. are the first tests done; pancytopenia and peripheral blasts suggest acute leukemia. Blast cells in the peripheral smear may approach 90% of the white blood cell (WBC) count. Aplastic Anemia , viral infections such as Bone marrow examination(aspiration and needle biopsy) is routinely done. Blast cells in the bone marrow are typically between 25 and 95% in patients with ALL. Histochemical studies, cytogenetics, and immunophenotyping studieshelp distinguish the blasts of ALL from those of AML or other disease processes. Histochemical studies include staining for terminal deoxynucleotidyl transferase (TdT), which is positive in cells of lymphoid origin. Detection of specific immunophenotypic markers such as CD3 (for lymphoid cells of T cell origin) and CD19, CD20, and CD22 (for lymphoid cells of B cell origin) is essential in classifying the acute leukemias. Common cytogenetic abnormalities in ALL include t(9;22) in adults and t(12;21) and high hyperdiploidy in children (see table). Less common cytogenetic abnormalities include the following: t(v;11q23) /MLLorKMT2Arearranged, including t(4;11)/KMT2A-AF4 t(1;19)/E2A-PBX1(TCF3-PBX1) t(5;14)/IL3-IGH t(8;14), t(8;22), t(2;8)/C-MYCrearranged BCR-ABL-like acute lymphoblastic leukemia overlaps phenotypically with ALL in which the Philadelphia chromosome [a reciprocal balanced translocation between chromosomes 9 and 22, t(9;22)] is present (Ph+ ALL). Other laboratory findings may include hyperuricemia, Hyperphosphatemia , CT of the head is done in patients with CNS symptoms. CT of the chest and abdomen should be done to detect mediastinal masses and lymphadenopathy and may also detect hepatosplenomegaly. Echocardiography or multi-gated acquisition (MUGA) scanning is typically done to assess baseline cardiac function (prior to administration of anthracyclines, which are cardiotoxic). 