Twenty-five year survival of chronic granulocytic leukaemia with spontaneous karyotype conversion.

Following busulphan-induced bone marrow hypoplasia a woman with chronic granulocytic leukaemia has survived 25 years from diagnosis. Since the last course of busulphan therapy in 1959 she has remained in clinical and haematological remission. Repeated cytogenetic analysis of bone marrow showed Philadelphia chromosome mosaicism with a minority of abnormal metaphases till 1969. Analysis of 150 metaphases in 1982 revealed no cells containing the Philadelphia chromosome. The possible significance of this spontaneous karyotype conversion is discussed.