A case of CML terminating in megakaryoblastic crisis is reported.
A 30-year-old female was admitted to our hospital because of high fever. Three months before admission, she was diagnosed as having CML from the findings of leukocytosis in the peripheral blood, low NAP score and presence of Ph1 chromosome, and treated with busulfan thereafter. Physical examination on admission revealed marked hepatosplenomegaly, lymphadenopathy and skin eruptions.
The white cell count in the peripheral blood was 100,000/μl with 81% blast cells. The blast cells exhibited a uniform size of 20 μm in diameter and had a large nucleus with homogeneous chromatin, and 1 or 2 nucleoli. The cytoplasm was abundant, basophilic and contained few granules. A few cells showed cytoplasmic blebs. The blast cells were peroxidase-negative, PAS-negative, α-naphthyl acetate esterase-positive, and acid phosphatase-positive. Ultrastructural studies revealed that the blast cells contained platelet-peroxidase in the endoplasmic reticulum and nuclear membrane distinct from myeloperoxidase. From these findings, she was diagnosed as having CML terminating in megakaryoblastic crisis.
She did not respond to a combination chemotherapy including vindesine and prednisolone, and died one month and a half after admission.
It is interesting to note that chromosomal abnormalities such as duble Ph1, 8 trisomy and t(1; 3) were observed. The relationship between megakaryoblastic crisis and t(1; 3) was discussed.
