The Leukaemias

Abstract

Acute leukaemia is the commonest form of malignant disease in childhood, accounting for nearly half of all childhood deaths from cancer. Because the aetiology is unknown and the clinical and haematological features are so variable, leukaemia is easier to describe than to define. Basically it is an abnormal proliferation of haemopoietic, particularly leukopoietic, tissues, abnormal in being non-purposeful, not self-limiting and steadily progressive to a fatal termination. Furthermore, this proliferation occurs at the expense of other blood-forming tissues which are progressively replaced. Although leukaemia is usually thought to be synonymous with a high white cell count (hence the name leukaemia or “white blood”) this is by no means typical, especially in childhood, where nearly half the cases have a normal or reduced total white cell count at the time of diagnosis. The term “aleukaemic leukaemia” is applied to this variation but it serves no useful purpose and should be abandoned. Before examination of the bone marrow became a common practice, recognition of this form of the disease was often difficult and many cases were misdiagnosed in children, being classified as obscure forms of anaemia. There seems little doubt that the disease was underdiagnosed before 1939 and this accounts, in part, for the apparent increase in incidence during subsequent years.