RT Book, Section
A1 Lichtman, Marshall A.
A1 Kaushansky, Kenneth
A1 Prchal, Josef T.
A1 Levi, Marcel M.
A1 Burns, Linda J.
A1 Linch, David C.
SR Print(0)
ID 1189333694
T1 Polyclonal Erythrocytoses (Primary and Secondary)
T2 Williams Manual of Hematology, 10e
YR 2022
FD 2022
PB McGraw-Hill Education
PP New York, NY
SN 9781264269204
LK hemonc.mhmedical.com/content.aspx?aid=1189333694
RD 2025/07/20
AB Erythrocytosis,  also  referred  to  as  polycythemia,  is  characterized  by  an  increased  red  cell  mass.  There  is  no  consensus  on  terminology  as  it  relates  to  the  choice  of  erythrocytosis  or  polycythemia  (ie,  primary  familial  and  congenital  polycythemia  but  postrenal  transplantation  erythrocytosis).  Herein,  the  term  polycythemia  will  only  be  used  for  polycythemia  vera,  an  acquired  clonal  disorder  caused  by  somatic  mutations  (Chap.  42),  and  polyclonal  erythrocytosis  will  be  used  for  all  other  states  discussed  in  this  chapter.An  erythrocytosis  can  be  primary  or  secondary  and  can  be  inherited  or  acquired.Classification  of  polycythemic  disorders  appears  in  Table  2–2  in  Chap.  2.A  primary  polycythemia/erythrocytosis  is  caused  by  somatic  or  germline  mutations  within  hematopoietic  stem  cells  or  erythroid  progenitors  that  result  in  an  augmented  response  to  erythropoietin  (EPO).  This  response  is  not  a  compensation  for  hypoxia  and  thus  is  inappropriate  for  tissue  needs.A  secondary  erythrocytosis  is  caused  by  either  an  appropriate  (compensatory)  or  inappropriate  increase  in  the  red  cell  mass  and,  in  most  instances,  results  from  an  augmented  level  of  EPO.