Bone marrow fibrosis and radiological changes of the long bones in children with acute megakaryocytic leukaemia.

The diagnosis of acute megakaryocytic leukaemia (AMkL) may be difficult to establish owing to difficulties in obtaining adequate bone marrow aspirates secondary to bone marrow fibrosis. We describe three children without Down's syndrome under 2 y of age with AMkL. Although none of the patients had the non-random t(1;22) (p13;q13) translocation, bone marrow cells from all patients exhibited chromosome abnormalities with complex karyotypes, including trisomy 21 in two cases. All patients had profound bone marrow fibrosis and characteristic lamellar diaphyseal radiological changes of the long bones.