274 The Lymphocyte and Lymphocytic Tissue 



granulation, commonly neutrophilic, less frequently eosinophilic or baso- 

 philic. So common is this tendency of the leukemic RE cell to bizarre 

 granulocyte formation that the nuclear lobulations mistakenly interpreted 

 as "monocytic" in connotation are more often evidence of precocious granu- 

 locytic nuclear segmentation prior to specific granule formation. It has thus 

 come about that in recent years granulocytic leukemic reticuloendotheliosis 

 (i.e., a monocytic leukemia with leukemic granulocytes) has been recognized 

 under the term "myelomonocytic leukemia." 



Fig. 19-11. Central group of two lymphoblasts and a prolymphocyte 

 as well as a medium-sized lymphocyte in mitosis from a lymph node 

 imprint in infectious mononucleosis. Leishman stain. (xllOO) 



Less common than granulocytic leukemic reticuloendotheliosis is the 

 leukemic process in which the hematopoietic RE cells show some differentia- 

 tion to leukemic erythroblasts, and thus erythrocytic leukemic reticulo- 

 endotheliosis is a frequent type among the rare group of the acute 

 erythrocytic leukemias. 



It is interesting that lymphocytic leukemic reticuloendotheliosis, i.e., a 

 leukemia in which the hematopoietic RE cells show obvious differentiation 

 to immature lymphocytes (lymphoblasts and prolymphocytes), is less com- 

 mon than its granulocytic counterpart (myelomonocytic leukemia). If such 

 an admixture of hematopoietic RE cells and immature lymphocytes is 

 infrequent in the leukemias, the opposite is the rule in the malignant 

 lymphomas of a comparable degree of immaturity. Thus, in malignant 



