A mother brings her 2-year-old boy with short history of pallor. Examination reveals pallor, petechiae and splenomegaly. Which of the following is the most likely diagnosis?
(a) Thalassaemia
(b) Acute leukaemia
(c) Hodgkin’s lymphoma
(d) Idiopathic thrombocytopenic purpura
Answer: b (Acute leukaemia)
The features given above closely resemble acute leukaemia (ALL) and ITP. But splenomegaly is uncommon in ITP. ITP is most common cause of acute onset of petechiae and purpura in children.
Some important points regarding ALL. It is most common malignancy of childhood. Radiation and toxins (benzene) are leukemogenic. Other chemotherapeutic agent like cyclophosphamide, melphalan and other alkylating agents (all have abnormality at chromosome 5,7) and etoposide (abnormality at chromosome11q23); M>F; peak incidence 2–5 years.
Symptom varies from days to week (mostly 3–4 weeks). Features are mainly due to bone marrow infiltration with leukaemic cell (bone marrow failure) and extramedullary disease.
Features are anaemia, thrombocytopenia, neutropenia, pallor, petechiae, purpura, bleeding and infection (due to neutropenia; most common Gram-negative organism, (E. coli, Klebsiella, Pseudomonas or fungi).
Massive bleeding may be due to DIC.
Lymphadenopathy, hepatomegaly, splenomegaly (>60%).
Bone pain due to involvement of periosteum.
CNS involvement (2–3%; mostly asymptomatic few have increase intracranial pressure).
Diagnosis of CNS involvement on examination of CSF (even a single blast cell is diagnostic).
Testicular leukaemia (1%) present with painless swelling of testis (diagnosed by biopsy).
Other rare sites of extramedullary involvement include heart, lung, kidney, ovaries, skin, eyes, or gastrointestinal tract.