Primary myelofibrosis terminating in megakaryoblastic crisis.

Primary myelofibrosis terminating in megakaryoblastic crisis is uncommon. A case with this condition is reported. The patient, a 62-year-old female, having had primary myelofibrosis for 13 years and a splenectomy 4 years before, was admitted because of high fever, hepatomegaly, thrombocythemia and leukocytosis. On admission, blasts appeared in the peripheral blood and thereafter gradually increased in number. The blasts were proven to be of megakaryocytic lineage. To our knowledge this is the third case of primary myelofibrosis terminating in megakaryoblastic crisis to be reported in Japan.