Chapter 105. Malignancies of Lymphoid Cells (Part 11)

Clinical Features, Treatment, and Prognosis of Specific Lymphoid MalignanciesPrecursor Cell B Cell NeoplasmsPrecursor B Cell Lymphoblastic Leukemia/LymphomaThe most common cancer in childhood is B cell ALL. Although this disorder can also present as a lymphoma in either adults or children, presentation as lymphoma is rare.The malignant cells in patients with precursor B cell lymphoblastic leukemia are most commonly of pre-B cell origin. Patients typically present with signs of bone marrow failure such as pallor, fatigue, bleeding, fever, and infection related to peripheral blood cytopenias. Peripheral blood counts regularly show anemia and thrombocytopenia but might show leukopenia, a normal leukocyte...
Nội dung trích xuất từ tài liệu:
Chapter 105. Malignancies of Lymphoid Cells (Part 11) Chapter 105. Malignancies of Lymphoid Cells (Part 11) Clinical Features, Treatment, and Prognosis of Specific LymphoidMalignancies Precursor Cell B Cell Neoplasms Precursor B Cell Lymphoblastic Leukemia/Lymphoma The most common cancer in childhood is B cell ALL. Although thisdisorder can also present as a lymphoma in either adults or children, presentationas lymphoma is rare. The malignant cells in patients with precursor B cell lymphoblasticleukemia are most commonly of pre-B cell origin. Patients typically present withsigns of bone marrow failure such as pallor, fatigue, bleeding, fever, and infectionrelated to peripheral blood cytopenias. Peripheral blood counts regularly showanemia and thrombocytopenia but might show leukopenia, a normal leukocytecount, or leukocytosis based largely on the number of circulating malignant cells(Fig. 105-5). Extramedullary sites of disease are frequently involved in patientswho present with leukemia, including lymphadenopathy, hepato- or splenomegaly,CNS disease, testicular enlargement, and/or cutaneous infiltration. Figure 105-5 Acute lymphoblastic leukemia. The cells are heterogeneous in size, haveround or convoluted nuclei, high nuclear/cytoplasmic ratio, and absence ofcytoplasmic granules. The diagnosis is usually made by bone marrow biopsy, which showsinfiltration by malignant lymphoblasts. Demonstration of a pre-B cellimmunophenotype (Fig. 105-2) and, often, characteristic cytogenetic abnormalities(Table 105-6) confirm the diagnosis. An adverse prognosis in patients withprecursor B cell ALL is predicted by a very high white cell count, the presence ofsymptomatic CNS disease, and unfavorable cytogenetic abnormalities. Forexample, t(9;22), frequently found in adults with B cell ALL, has been associatedwith a very poor outlook. The bcr/abl kinase inhibitors have improved theprognosis. Precursor B Cell Lymphoblastic Leukemia: Treatment The treatment of patients with precursor B cell ALL involves remissioninduction with combination chemotherapy, a consolidation phase that includesadministration of high-dose systemic therapy and treatment to eliminate disease inthe CNS, and a period of continuing therapy to prevent relapse and effect cure.The overall cure rate in children is 90%, while ~50% of adults are long-termdisease-free survivors. This reflects the high proportion of adverse cytogeneticabnormalities seen in adults with precursor B cell ALL. Precursor B cell lymphoblastic lymphoma is a rare presentation ofprecursor B cell lymphoblastic malignancy. These patients often have a rapidtransformation to leukemia and should be treated as though they had presentedwith leukemia. The few patients who present with the disease confined to lymphnodes have a high cure rate. Mature (Peripheral) B Cell Neoplasms B Cell Chronic Lymphoid Leukemia/Small Lymphocytic Lymphoma B cell CLL/small lymphocytic lymphoma represents the most commonlymphoid leukemia, and when presenting as a lymphoma, it accounts for ~7% ofnon-Hodgkins lymphomas. Presentation can be as either leukemia or lymphoma.The major clinical characteristics of B cell CLL/small lymphocytic lymphoma arepresented in Table 105-10.