Bone marrow involvement is not manifest in the early stages of childhood acute lymphoblastic leukaemia.

INTRODUCTION: Acute lymphoblastic leukaemia (ALL) in children may have atypical presentations causing diagnostic delay. Guidelines for prompt referral have been published. The utility of the specified criteria is unknown. MATERIAL AND METHODS: Symptoms, signs and laboratory findings at the time of diagnosis were reviewed in a consecutive series of 100 children with ALL in order to determine the frequency of atypical features and to evaluate the Danish referral guideline. RESULTS: Only 36% had involvement of all three haematopoietic cell lines, and 23% presented with the classic clinical triad of pallor, fever and purpura. Symptoms of bone marrow insufficiency had been present in 77% for an average of two weeks as a late occurrence following musculoskeletal pains (in 49%, duration eight weeks) and constitutional symptoms (in 82%, duration four weeks). Organ infiltration was manifest in 71%. In 22%, only one or no cell count was abnormal; in this group, musculoskeletal symptoms were more frequent and symptom duration longer (two months versus one month). In 15%, lymphoblasts could not be detected in the blood. At the time of diagnosis, the Danish criteria for accelerated investigation were fulfilled in 98% of cases. CONCLUSION: The clinical presentation of ALL is variable, and full-blown bone marrow insufficiency is a late occurrence as the disease progresses. Reduction of the diagnostic interval requires meticulous examination for organomegaly and attention to subtle haematologic changes. FUNDING: Not relevant. TRIAL REGISTRATION: Not relevant.