Myelofibrosis and rapid thrombocytolysis. A case report

A 69-year-old woman was referred to our department because of moderate anemia and thrombocytopenia. On admission the spleen was slightly enlarged. On the basis of histological examination of biopsy specimens from spinal processes the diagnosis of myelofibrosis was made. The subsequent clinical course was progressively downhill. Although splenomegaly was of only moderate degree, severe anemia and thrombocytopenia supervened. Platelet mean life span was dramatically shortened (1.8 hours) and platelet production rate considerably increased (about 18xnormal). Neither corticosteroid therapy nor splenectomy alleviated the thrombocytopenia. Extremely large platelets, with diameters of up to 10 mum, were seen in the peripheral blood. The mean platelet diameter and percentage of megathrombocytes reached peak values about 2 weeks after splenectomy. It is suggested that the immunologic background of the rapid thrombocytolysis is similar to that which governs platelet destruction in idiopathic thrombocytopenic purpura.