The cell indicated by the arrow is an E1 cell or pronormoblast. E1 cells are rare in normal marrow but may be seen in hemolytic anemias and other hematologic disorders when there is also erythroid hyperplasia. E1 cells vary in size from 20-25 microns. The cytoplasm is deeply basophilic and darker than the nucleus. It generally surrounds the nucleus. The arrow indicates the area of the unstained Golgi body. This light spot in the cytoplasm is extremely valuable in differentiating red cell blasts from white cell blasts. There is a light area around the nucleus that includes the negative images of mitochondria. The nucleus is large and the nucleus-to-cytoplasm ratio (N:C) is about 6:1. The nuclear chromatin is fine and homogeneous. The entire nucleus has a reddish cast. The small nucleoli stain darker than in white cell blasts; they often are obscured by the chromocenters. They are not prominent in this cell.
Course Section: 05. Nucleated Red Blood Cells
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