Double Ph1 chromosomes in chronic granulocytic leukemia

Two cases of chronic granulocytic leukemia were considered atypical because abnormal “monocytoid” granulocytes and morphological abnormalities of the erythrocytes were present. This suspicion was confirmed by the course of the disease and by the existence of several abnormal chromosome cell lines in both patients, including double Ph1 chromosomes. The presence of Ph1 chromosomes suggested the patients were in a “preblastic” stage of chronic granulocytic leukemia, particularly since double Ph1 chromosomes have been reported in the terminal stages of other cases of this type of leukemia.