This page compiles our content related to leukaemia. For further information on diagnosis and treatment, follow the links below to our full BMJ Best Practice topics on the relevant conditions and symptoms.
Introduction
Relevant conditions
Acute lymphoblastic leukaemiaSigns & symptomsInvestigationsDifferentialsTreatment algorithm | go to our full topic on Acute lymphoblastic leukaemia A malignant clonal disease that develops when a lymphoid progenitor cell becomes genetically altered through somatic changes and undergoes uncontrolled proliferation. This progressive clonal expansion eventually leads to acute lymphoblastic leukaemia (ALL), characterised by early lymphoid precursor cells replacing the normal haematopoietic cells of the bone marrow and further infiltrating various body organs.[4][5] ALL can occur at any age, but more than one-half of all cases (52.7%) are diagnosed in those aged under 20 years.[6] B-ALL (arising from B lymphoid progenitors) accounts for approximately 75% of adult cases, with the remainder being predominantly T-ALL (arising from T lymphoid progenitors).[7] Most ALL patients have signs and symptoms related to cytopenias (e.g., fatigue, easy bruising) at presentation and diagnosis. Enlarged lymph nodes can be an initial presenting sign. Key diagnostic factors include young age (children aged <5 years); presence of genetic disorders (e.g., trisomy 21); family history of ALL; personal history of malignancy; treatment with chemotherapy; exposure to radiation; smoking; and folate metabolism polymorphisms. |
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Chronic lymphocytic leukaemiaSigns & symptomsInvestigationsDifferentialsTreatment algorithm | go to our full topic on Chronic lymphocytic leukaemia Chronic lymphocytic leukaemia (CLL) is the most common leukaemia in the western world.[8][9] It represents 1% of all new cancer cases in the US.[10] CLL is an indolent lymphoproliferative disorder in which monoclonal B lymphocytes (≥5000 cells/microlitre [≥5 x 10⁹/L]) are predominantly found in peripheral blood.[11] The exact cause of CLL is unclear, but it is thought to develop as a result of an accumulation of multiple genetic events affecting oncogenes and tumour suppressor genes, which leads to increased cell survival and resistance to apoptosis.[12] Key diagnostic factors include lymphadenopathy, hepatosplenomegaly, shortness of breath and fatigue. Most cases of CLL are diagnosed incidentally following a routine full blood count (FBC) for an unrelated reason.[13] |
Acute myeloid leukaemiaSigns & symptomsInvestigationsDifferentialsTreatment algorithm | go to our full topic on Acute myeloid leukaemia A life-threatening haematological malignancy caused by the clonal expansion of myeloid blasts in the bone marrow, peripheral blood, or extra-medullary tissues. Occurs predominantly in older adults.[2] In 2025, there will be an estimated 22,010 new cases of acute myeloid leukaemia (AML) and 11,090 deaths related to AML in the US.[2] Risk factors include previous treatment with chemotherapy, a previous haematological disorder (e.g., aplastic anaemia, myelodysplastic syndrome), inherited genetic disorders (e.g., Bloom syndrome, Wiskott-Aldrich syndrome), and exposure to radiation, benzene, or alkylating agents. Pallor, ecchymoses, and petechiae are common findings. Diagnosis requires bone marrow aspirate and trephine biopsy analysis. |
Chronic myeloid leukaemiaSigns & symptomsInvestigationsDifferentialsTreatment algorithm | go to our full topic on Chronic myeloid leukaemia A malignant clonal disorder of the haematopoietic stem cell that results in marked myeloid hyperplasia of the bone marrow.[14] Incidence peaks between the ages of 65 and 74 years, but people of all ages can be affected.[2] Possible signs and symptoms include splenomegaly, dyspnoea, abdominal discomfort, malaise, fever, and night sweats; approximately 50% of patients are asymptomatic.[15] All patients require bone marrow biopsy. Presence of Philadelphia chromosome and/or molecular demonstration of the BCR::ABL1 transcript confirms diagnosis. |
Blast crisisSigns & symptomsInvestigationsDifferentialsTreatment algorithm | go to our full topic on Blast crisis Blast crisis refers to the transformation of chronic myeloid leukaemia (CML) from the chronic or accelerated phase to the blast phase. Diagnosis is confirmed by the percentage of blast cells (≥20% [WHO criteria] or ≥30% [MD Anderson Cancer Center and the International Bone Marrow Transplant Registry criteria]) in the peripheral blood or bone marrow.[16][17][18][19] The Philadelphia chromosome is present in >95% of cases of CML and is a hallmark of this disease. Anaemia, infections, abnormal/excessive bleeding, bone pain, or constitutional symptoms (night sweats, weight loss, fever) are common presenting complaints of blast-phase CML. History of CML and exposure to alkylating chemotherapeutic agents are risk factors for blast crisis. |
Hairy cell leukaemiaSigns & symptomsInvestigationsDifferentialsTreatment algorithm | go to our full topic on Hairy cell leukaemia A relatively uncommon, indolent mature B-cell neoplasm. Hairy cell leukemia (HCL) is considered to be a type of non-Hodgkin's lymphoma. Seen under the microscope, the leukaemic cells have delicate cytoplasmic projections resembling hair ('hairy cells'). HCL is commonly characterised by symptoms of fatigue, a markedly enlarged spleen, and pancytopenia. To confirm the diagnosis, a bone marrow trephine biopsy and aspiration should be carried out for morphology assessment and immunophenotyping (using immunohistochemistry or flow cytometry).[20] |
Assessment of pancytopeniaDifferentials | go to our full topic on Assessment of pancytopenia Pancytopenia is a reduction in the number of red blood cells, and platelets, in the peripheral blood below the lower limits of the age-adjusted normal range for healthy people. The causes are diverse, and likely differ in children and adults. The presence of pancytopenia always warrants investigation by a haematologist. Leukaemias may cause pancytopenia through decreased production, or increased destruction or sequestration, of blood cells. |
Assessment of neutropeniaDifferentials | go to our full topic on Assessment of neutropenia Neutrophils are essential components of the haematopoietic and immune system, and quantitative or qualitative abnormalities of neutrophils can result in life-threatening infection. Infections are the most common cause of neutropenia in adults, followed by drug-induced neutropenias. In children <2 years of age, primary autoimmune neutropenia is the most common cause. Absolute neutrophil count is generally used to grade neutropenia severity. |
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References
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