Childhood Acute Lymphoblastic Leukemia (ALL)

Acute lymphoblastic leukemia (ALL) is a malignant blood disease and the most common type of cancer in children. In this condition, the bone marrow produces a large number of lymphoblasts—immature lymphocytes that do not differentiate into B- or T-cells and are unable to perform their normal protective functions. These abnormal cells suppress normal hematopoiesis, leading to anemia, bleeding tendencies, and increased susceptibility to infections.

ALL occurs most frequently in children between 2 and 5 years of age. The five-year event-free survival rate is 80–90%; however, in infants (under 1 year) and in adolescents aged 15 years and older, survival is relatively lower due to unfavorable genetics and a more aggressive disease course.

The exact cause of ALL remains unknown. The disease results from genetic and cellular abnormalities in hematopoietic cells.

Risk factors include genetic syndromes (Down syndrome, Bloom syndrome, Fanconi anemia, ataxia telangiectasia, etc.), certain chromosomal and gene alterations, radiation exposure, and previous chemotherapy.

In children, the disease may present with an acute onset, including high fever, pronounced intoxication, and joint pain. About 10% of patients experience nasal or gingival bleeding, as well as bruising and petechiae on the skin and mucous membranes.

In cases with a more insidious onset, nonspecific manifestations predominate: progressive weakness, fatigue, pallor, reduced physical performance, weight loss, decreased appetite, musculoskeletal pain, fever (recurrent or unexplained), and frequent or prolonged infections.

The main clinical signs include:

Pllor
Hemorrhagic syndrome, bruising, petechiae
Bone and joint pain
Enlargement of lymph nodes, liver, and/or spleen
Respiratory distress and chest pain (in the case of mediastinal mass)
Less commonly, involvement of the central nervous system (CNS) and testicular infiltration in boys

Diagnosis begins with a thorough medical history, physical examination, and peripheral blood smear morphology. The diagnosis is confirmed by identifying 20% or more blast cells in peripheral blood and/or bone marrow. CNS involvement may be established by detecting blast cells in cerebrospinal fluid or, clinically, when neurological signs are present.

Treatment approaches include chemotherapy, immunotherapy, targeted therapy, radiotherapy, and allogeneic stem cell transplantation (SCT).