[CITATION][C] Some speculations on the myeloproliferative syndromes

W Dameshek - Blood, 1951 - ashpublications.org
W Dameshek
Blood, 1951ashpublications.org
ACCUMULATING EXIERIENCE, it becomes more and more evident that the bone marrow
cells-enythrobhasts, granulocytes, megakar-vocvtes-often proliferate en masse or as a unit i-
ather than as single elements. Thus, heukocytosis an (h thIOml) OcytOsis, as well as
reticuhocytosis occur not only in 1) enign reversible cond! itions such as hemorrhage and
excessive hemolysis 1) tlt in such malignant or-more or less irreversible reactions as
leukemia and! pohycythemia. Although we seem to have become conditionet! to the idea …
ACCUMULATING EXIERIENCE, it becomes more and more evident that the bone marrow cells-enythrobhasts, granulocytes, megakar-vocvtes-often proliferate en masse or as a unit i-ather than as single elements. Thus, heukocytosis an (h thIOml) OcytOsis, as well as reticuhocytosis occur not only in 1) enign reversible cond! itions such as hemorrhage and excessive hemolysis 1) tlt in such malignant or-more or less irreversible reactions as leukemia and! pohycythemia. Although we seem to have become conditionet! to the idea that such entities as chronic gianulocytic leukemia and pohycythemia vera represent “pule” prohifemations of one or another cell type, a revision in this thinking max’be necessary. Foi example, in most early cases of chronic granuiocytic leukemia, there is some dhegIee of eiythmocytosis and thrombocytosis. The latter may be of extraoidinary degree and attended with the presence of bits of megakai-yocvtes in the cim-culation. Thrombocvtosis often persists until the very end! of the d! isease and at times may dominate the picture. Simiharly, pohycythemia vera is far more than a pure red cell proliferation. The 1) 100 (1 picture ieveahs pancytosis’(erythi-ocytosis, leukocytosis, thrombocy-tosis) an (l the marrow shows generalized hypercelluharity often dominated! by extieme increases in the megakaryocytes. Some cases of othetwise clear-cut 1) ol’(-themia have leukocvte counts in the neighborhoodl of 50,000 to 100, 06’O with fain miumbers of myelocytes in the 1) 100 (1. How should one t-lassify these cases? Aie they atypical granulocytic leukemia with erythrocytosis resembhing polycytisensia vema or are they examples of polycythemia vera with a heukemoidl ieactiofl. Ims some cases of polycythemia slRwving relatively slight emythmocytosis, the platelet count may reach levels of five to ten million l) e1 cu. mm. ttIidl the tiir-oml) ocvtociit max’be 5 to 10 per cent of the total volume. 1) o these cases i-epi-esent a vai-iant of polycythemia or are they perhaps a pro-lifer-ati ye disordlel of the megakaryocytes, eg megakaryocytic leukemia? In about 10 to 20 per cent of all cases of pohycythemia veta there is the gradual (levehopment of increasing anemia with a ‘leuko-erythrobhastic” bhood! picture. The bone mat-row in su (-h cases shows a stiiking fibiosis andl the spheen shows well deitned marrow activity(myeloid! metaphasia). In the past, it was simple to consider the ext m-ametlulhamy hematopoiesis in the spleen as being purely compen-satory in nature.[however, it is apparent that individuals ultimately d! evehoping nyelofil) rosis i-an often be ‘spotted” yeai. s in advance by the marked degree of splenomegaly presenst and by the presence of small numbers of nucieate (l i-ed cells ann mvehocvtes in the blood em-en when the marrow is b!/no means fibrotic and the i-en! cell count is still elevatenh. This brings up the (listinct possibility that the splenomegaly, which is due largely to myehoinh metaplasia, has been present fon-yeas-s. The gi-adually developing fibrosis of the marrow may be simply another manifestation of man-ow proliferation, 2 in this instance involving
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