Hairy cell leukemia:report of a case

Hairy cell leukemia （HCL） is an uncommom type of leukemia,characterized by an insidiousonset,a triad of pancytopenia,splenomegaly,circulating hairy cells and indolent clinical course.The average age at the time of diagnosis is in the fifth decades.It is rarely seen in children.Wehave encountered a 9 month-old baby with HCL and report here with.Our case showed some di-fferences from adults as follows （1） the onset was acute rather than insidious;（2） the splenomegalywas not marked;（3） the pancytopenia was transient;（4） dry aspiration in bone marrow was notencountered.The possible mechanism of the differences were discussed.