Abnormal (marker) chromosomes in two patients with acute myelofibrosis.

Abstract

Acute myelofibrosis is a condition belonging to the group of acute myeloproliferative disorders (Dameshek and Gunz 1 ). Lewis and Szur, 2 under the term malignant myelosclerosis, described it as occurring in people older than 40 and characterized by rapidly developing anemia and thrombocytopenia. The spleen is usually not palpable and certainly not as massively enlarged as in chronic myelofibrosis with myeloid metaplasia. The largest spleen in their group of five weighed 550 gm. The dominant features of the hematologic examination are anemia with some poikilocytosis, leukopenia with a small percentage of blasts and a few nucleated red blood cells (RBCs) in the peripheral blood, and thrombocytopenia. Bone marrow is difficult to obtain by aspiration and if any fragments are withdrawn they show some blasts, a few reticulum cells, and megakaryocytes. Bone marrow biopsy shows alteration of normal architecture with increase of collagen tissue and some hematopoietic elements. The course