Essay 11- Acute lymphoblastic leukemia (ALL)
Definition
- Malignancy of B or T lymphoblasts characterized by uncontrolled proliferation of abnormal, immature lymphocytes and their progenitors!
Etiology
- Incidence is highest at 3-7 years
- 85% are of B cell lineage
- A proportion of cases of childhood ALL are initiated by genetic mutations that occur during development in utero
- Polymorphic variants of ARD5B, IKZF1 and CDKN2A
- Environmental factors- benzene exposure, ionising radiation, previous chemo or radiotherapy
Classification
Table 17.1 Classification of acute lymphoblastic leukaemia (ALL) according to WHO (modified from WHO 2008; see also Appendix).
- B acute lymphoblastic leukaemia with recurrent genetic abnormalities
- ALL with t(12;21)
- ALL with t(9;22)
- ALL with t(11q23; variable)
- Hyperdiploidy (>50 chromosomes)
- Hypodiploidy (<45 chromosomes)
- T- acute lymphoblastic leukaemia
N.B. A minority of patients present with nodal or extranodal masses and <20% blasts in the marrow and are called lymphoblastic lymphoma if the tumour cells resemble those of ALL.
Symptoms
- Anemia- pallor, lethargy, dyspnea
- Neutropenia- fever, malaise, features of infections of mouth, throat, skin
- Thrombocytopenia- bruises, purpura, bleeding gums, menorrhagia
- Hepatosplenomegaly
- Night sweats
- Painless lymphadenopathy
- Bone pain- limping or refusal to bear weight in children
- Airway obstruction
- Features of SVC syndrome
- Meningeal leukemia- headache, neck stiffness, visual field changes
- Testicular enlargement (rare)