ACUTE-LEUKEMIA WITH MEGAKARYOCYTIC DIFFERENTIATION - A STUDY OF 12 CASES IDENTIFIED IMMUNOCYTOCHEMICALLY

  • 1 January 1984
    • journal article
    • research article
    • Vol. 64  (2) , 427-439
Abstract
Acute leukemia with megakaryocytic differentiation has been an uncommonly recognized disorder. Specific monoclonal and polyclonal antibody reagents (HP1-1D antibody and anti-factor VIII antibody, respectively) and an immunocytochemical staining technique were used to identify the megakaryocytic nature of the leukemic cells of 12 patients who presented with acute leukemia. The leukemic cells of patients demonstrated the presence of 1 or both of these platelet- and megakaryocyte-related antigens, but were negative for all of the commonly employed cytochemical and immunocytochemical staining reactions, except for diffuse acid phosphatase activity and granular PAS [periodic acid Schiff] positivity. Morphologically, the leukemic cells varied in size from 10-40 .mu.m in diameter, frequently had cytoplasmic budding, and contained occasional vacuoles and/or peroxidase-negative azurophilic granules. Five patients presented with syndromes of acute myelofibrosis, and 7 patients had otherwise unclassifiable acute leukemias, including 3 patients who had secondary leukemias. Diffuse reticulin myelofibrosis was present in all cases in which it was sought. Chromosomal abnormalities of leukemic cells were found in 5 cases. Two patients had deficiencies of plasma coagulation factor V. Study of 1 patient revealed significant platelet dysfunction. When cytoreductive chemotherapy of leukemia was attempted, the observed response was generally poor, with the exceptions of 1 patient who has remained in complete remission following treatment with etoposide (VP-16) and a 2nd patient who attained remission following bone marrow transplantation. These cases of acute megakaryoblastic leukemia represented from 3.6-9.3% of all acute leukemia cases diagnosed concomitantly. Acute leukemia with megakaryocytic differentiation may occur more frequently than previously recognized, may present with differing syndromic features, and can be identified by the use of specific antibody reagents and relatively simple immunocytochemical techniques.