promyelocyte early promyelocyte 2010-08-24T03:07:53Z A promyelocyte with a nucleus that is indented and contains more marginated heterochromatin compared to its precursor cell (myeloblast); cytoplasm is deeply basophilic and contains numerous mitochondria and meandering cysternae of endoplasmic reticulum; largest of the granulocyte lineages. FMA:83533