[Differential diagnosis of atypical chronic myeloid leukaemia].

Observations in six adult patients with leukaemic differential white counts, predominantly mature-celled, and with hepatosplenomegaly show that the mature-celled but fulminant (para-)neutrophil leukaemia must be differentiated from Ph1-positive chronic myeloid leukaemia. This (para-)neutrophil leukaemia is probably identical with the previously described atypical chronic myelosis of the adult, chronic myeloid leukaemia of childhood and the Pelger-like chronic myeloid leukaemia. Cardinal signs are a mature-celled differential count, short life expectancy (1 year), initial platelet deficiency, increased activity of granulocyte alkaline phosphatase, absence of Ph1-chromosome, and poor therapeutic response to busulfan. This curious and yet apparently not uncommon disease has been observed in the adult age group predominantly in men. The frequently high HbF level observed in juvenile chronic myeloid leukaemia could not be demonstrated in adults. Some of these neutrophil leukaemias are characterized by medullary fibrosis and terminal increase of immature blast cells (blast crises?) of which the diagnostic reliability is still disputed.