ABSTRACT
B-lymphoblastic leukaemia and B-lymphoblastic lymphoma are essentially one disease process. Those patients with predominantly blood and bone marrow involvement are designated as having leukaemia; those with nodal or extranodal disease and less than 25 per cent lymphoblasts in the bone marrow are designated as having lymphoma. In practice, the majority of cases are leukaemic. Although B-lymphoblastic leukaemia/lymphoma is approximately four times as common as T-lymphoblastic leukaemia/ lymphoma, the T-cell neoplasms present more frequently as a solid tumour (lymphoma).
