Acute lymphoblastic leukemia (ALL) is a malignant disorder of the bone marrow characterized by the proliferation of the lymphoid progenitor cells.
ALL is the commonest form of childhood leukemia, accounting for ~80% of pediatric leukemia cases 1. In adults, ALL corresponds to ~20% of leukemia cases 1.
Peak age is between 3 to 7 years, with a second peak over 40 years.
The clinical features of acute lymphoblastic leukemia are non-specific. Children commonly have at least one of pallor, fever, a palpable liver, a palpable spleen, or bruising on diagnosis 2. Other symptoms such as bone or joint pain, weight loss, anorexia, bleeding, abdominal pain and abdominal distension are also common.
In acute lymphoblastic leukemia, the lymphoid progenitor cells, also known as lymphoblasts, do not mature due to abnormal expression of genes, often as a result of chromosomal abnormalities or chromosomal translocations. The proliferation of the primitive cells takes up more and more marrow space at the expense of the normal hematopoietic elements, resulting in a decrease in the production of normal blood cells and bone marrow failure. Eventually, the lymphoblasts spill into the blood and can affect the liver, spleen, central nervous system, and lymph nodes.
Bone lesions are common in leukemia. A metaphyseal radiolucent band is one of the most important radiological finding 3. Other radiological findings include subperiosteal new bone formation and osteolytic lesions involving the medullary cavity and cortex 1,3-5.
Chest radiograph may reveal a mediastinal mass.
Treatment and prognosis
The treatment for ALL typically has three phases:
- induction therapy: combination chemotherapy is used to rapidly kill tumor cells with an aim to get the patient into remission
- consolidation phase: if remission is achieved, further chemotherapy is given during this phase to treat the residual disease
- maintenance phase: if the patient is still in remission after the consolidation phase, maintenance oral therapy is given
- this may last up to three years if the patient remains in remission
Pediatric patients with ALL have an overall five-year survival rate of 80% depending on their risk profile 6. However, only 30-40% of adults with ALL achieve long-term remission with the current treatment regimens 7.
For the ALL bony abnormalities, consider:
- 1. Rogalsky RJ, Black GB, Reed MH. Orthopaedic manifestations of leukemia in children. (1986) The Journal of bone and joint surgery. American volume. 68 (4): 494-501. Pubmed
- 2. Clarke RT, Van den Bruel A, Bankhead C, Mitchell CD, Phillips B, Thompson MJ. Clinical presentation of childhood leukaemia: a systematic review and meta-analysis. (2016) Archives of disease in childhood. 101 (10): 894-901. doi:10.1136/archdischild-2016-311251 - Pubmed
- 3. Müller HL, Horwitz AE, Kühl J. Acute lymphoblastic leukemia with severe skeletal involvement: a subset of childhood leukemia with a good prognosis. (1998) Pediatric hematology and oncology. 15 (2): 121-33. Pubmed
- 4. Gallagher DJ, Phillips DJ, Heinrich SD. Orthopedic manifestations of acute pediatric leukemia. (1996) The Orthopedic clinics of North America. 27 (3): 635-44. Pubmed
- 5. Heinrich SD, Gallagher D, Warrior R, Phelan K, George VT, MacEwen GD. The prognostic significance of the skeletal manifestations of acute lymphoblastic leukemia of childhood. (1994) Journal of pediatric orthopedics. 14 (1): 105-11. Pubmed
- 6. Hutter JJ. Childhood leukemia. (2010) Pediatrics in review. 31 (6): 234-41. doi:10.1542/pir.31-6-234 - Pubmed
- 7. Jabbour E, O'Brien S, Konopleva M, Kantarjian H. New insights into the pathophysiology and therapy of adult acute lymphoblastic leukemia. (2015) Cancer. 121 (15): 2517-28. doi:10.1002/cncr.29383 - Pubmed