Structure of Lymphocytic Series oj Cells in Relation to Disease 273 



entrenched in the American literature as a designation for the leukemic 

 overgrowth of blood-forming RE cells. 



In leukemias in which differentiation does not progress beyond the 

 hematopoietic RE cells (Fig. 19-9), the nucleus retains the reticulated or 

 stippled pattern of its nonleukemic counterpart, the nucleus is larger than 

 that of lymphoblasts or myeloblasts, and the cytoplasm is similarly much 

 more abundant than the cell body of either the leukemic lymphoblast or 

 myeloblast. Azurophilic granulation may be present or absent. Often the 



i * 



i 



Fig. 19-10. Hematopoietic reticulum cells that were also leukemia 

 but show all stages of transformation to true monocytes at far right. 

 Bone marrow of true acute monocytic leukemia, Schilling type. 

 Leishman stain. (X 1 100) 



large cell body fails to round up and drags along a broad tail or cyto- 

 plasmic streamer. Malignant lobulation of the nucleus can easily be mis- 

 interpreted as abortive attempts at monocyte formation (top cell of Fig. 

 19-9). It is very rare for the cells of leukemic reticuloendotheliosis (histio- 

 cytic leukemia) to show differentiation to mature human monocytes (Fig. 

 19-10). When such a rare case occurs, it is correctly designated as monocytic 

 leukemic reticuloendotheliosis or acute monocytic leukemia (Schilling). 

 More often, however, if the leukemic RE cells show some differentiation to 

 recognizable blood cell lines, such differentiation is manifested by grotesque 

 granulocyte formation on their part. The resultant granulocytes are charac- 

 terized by their large size, reticulum cell nuclear patterns, bizarre or malig- 

 nant nuclear lobulation, but with their telltale, specific cytoplasmic 



