Acute myelofibrosis in children with Down's syndrome.

Two boys with Down's syndrome, recognized at birth, developed acute myelogibrosis at the ages of 19 and 21 months. The disorder presented with anaemia and splenomegaly, and clinically resembled acute leukaemia, but bone marrow histology showed a bizarre pattern with generalized fibrosis, markedly increased reticulin, large reticulum cells, and giant cells resembling megakaryocytes. The children survived 6 and 11 months from diagnosis. A third case is quoted (Hillman and Forrester, 1968) which was also studied at this hospital; the features of all 3 cases are similar. There appears to be an increased incidence of acute myelofibrosis in children with Down's syndrome, which may be a further example of the instability of the haemopoietic system in the disease. In children with Down's syndrome and unusual leukaemia-like illness, histological examination of the bone marrow may be diagnostic.