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 1189333026
T1 Hereditary and Acquired Sideroblastic Anemias
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=1189333026
RD 2024/04/19
AB Sideroblastic  anemias  may  be  acquired  or  hereditary  and  are  classified  in  Table  11–1.Normal  red  cell  precursors  have  cytoplasmic  organelles  termed  siderosomes  that  contain  aggregated  iron-rich  ferritin.  They  can  be  seen  in  erythroblasts  by  transmission  electron  microscopy  and  represent  normal  structures  providing  iron  for  hemoglobin  synthesis.  These  aggregates  may  be  below  the  resolution  of  the  light  microscope.  Thus,  in  Prussian  blue–stained  marrow  specimens,  about  20%  to  40%  of  red  cell  precursors  have  one  to  three  very  small,  pinhead-sized  blue  granules  in  the  cytoplasm  under  oil  immersion  optics,  depending  on  the  quality  of  the  preparation.Pathologic  sideroblasts  are  of  two  types.  The  classical  type  is  a  ring  sideroblast  with  large,  Prussian  blue–stained  granules  in  a  circumferential  position  around  the  nucleus  of  the  erythroblast.  This  position  reflects  their  intramitochondrial  location:  mitochondria  in  erythroblasts  being  positioned  closely  surrounding  the  nucleus.  The  other  type  of  pathologic  sideroblast  has  large  and  multiple  cytoplasmic  granules  (see  Figure  11–1).Sideroblastic  anemias  are  characterized  by:—  A  population  of  hypochromic  and  normochromic  erythrocytes  in  the  blood  film  (dimorphic  picture).—  Increased  red  cell  precursors  in  the  marrow  in  the  face  of  anemia  and  a  low  reticulocyte  count.—  Anemia  that  is  the  result  of  apoptosis  of  late  erythroid  precursors  (ie,  ineffective  erythropoiesis),  with  increased  plasma  iron  turnover  and  normal  to  decreased  red  cell  survival.—  Drugs  that  reduce  the  formation  of  pyridoxal  5′-phosphate  from  pyridoxine  decrease  heme  synthesis  and  can  cause  sideroblastic  anemia.