Abstract
Acute lymphoblastic leukaemia (ALL) presenting as a transient pancytopenia is known to occur in children and less commonly in adults. The period of pancytopenia usually resolves after about 5–38 weeks, to be followed by overt ALL. The pathogenesis is not known and there are no specific cytogenetic abnormalities. Diagnosis is often difficult during the period of bone marrow hypoplasia. Quantitative flow cytometry can help to establish early diagnosis, and can be used on more patients presenting in a similar way.