Extramedullary infiltrates at diagnosis have no prognostic significance inchildren with acute myeloid leukaemia

This retrospective study was designed to review the relative frequency and prognostic significance of extramedullary infiltrates in children with acut e myeloid leukaemia (AML), The registration data and initial discharge summ aries were reviewed for all children diagnosed with AML, and registered by the Dutch Childhood Leukaemia Study Group (DCLSG), Between 1972 and 1998, 4 77 children were diagnosed with AML, Of these patients, 120 (25.1%) had ext ramedullary leukaemia (EML) at diagnosis. Four categories of EML were found : skin, soft tissue or bone, gingival infiltration and central nervous syst em (CNS) involvement. Patients who presented with gingival infiltrates, wer e older than those without EML or those in the other EML subgroups, had a h igh initial WBC count and a high proportion of M4/M5 morphological variants . This type of presentation could indicate a special biological entity. Uni variate analysis of prognostic factors in patients treated after 1985 with intensive protocols showed that initial WBC count and the presence of favou rable cytogenetic findings were significant, The presence of EML at diagnos is had no significant effect on event-free survival, In a stepwise multiple regression analysis only favourable cytogenetic findings remained signific ant.