Histochemistry of Lymphocytic Tissue in Malignant Lymphomas 197 



red precipitate in the sinus histiocytes, while the follicles were pale clue to 

 the lesser activity of the lymphocytes. In imprints of a lymph node stained 

 to demonstrate acid phosphatase, the large cells with the intense staining 

 reaction were histiocytes while the lymphocytes contained only minute, 

 scattered granules. With previously utilized techniques, it was not possible 

 to demonstrate acid phosphatase in lymphocytes. In normal blood smears 

 stained to demonstrate esterase, the monocyte was strongly positive in con 

 trast with the lack of staining in neutrophils. Similar smears demonstrated 

 strong acid phosphatase activity in the blood monocyte. 



HYDROLYTIC: ENZYMES IN LYMPHOID DISEASES 



Table 16-2 illustrates the distribution of the same enzymes in lymphoid 

 diseases. Note that the epithelioid cells of granulomas manifest similar ac- 

 tivity to histiocytes 8 but with increased leucine aminopeptidase activity. 

 Proliferating fibroblasts in areas of inflammation and in Hodgkin's disease 

 are strongly positive for acid and alkaline phosphatases and leucine amino- 

 peptidase. The cells of histiocytic lymphoma and monocytic leukemia are 

 qualitatively identical with their normal counterparts.- 8 Indeed, stem cell 

 lymphoma may be distinguished from the histiocytic type on the basis of its 

 lack of enzyme activity. Sternberg cells and tumor histiocytes of Hodgkin's 

 disease also manifests similar activity to that of normal histiocytes.-' 8 One 

 observation of possible significance is that while acid phosphatase and leucine 

 aminopeptidase activities are high in these neoplastic histiocytes, many cells 

 seem to manifest diminished esterase activity in contrast to normal histio- 

 cytes. Lymphocytic lymphoma cells are inactive with the probable exception 

 of acid phosphatase. In the blood, leukemic lymphocytes manifest acid 

 phosphatase activity virtually universally. In one case of follicular lym- 

 phoma, activity of lymphocytes resembled that seen in the diffuse form. 



When a type of lymphoma demonstrating the pattern of total replacement 

 by proliferating histiocytes characteristic of histiocytic lymphoma was stained 

 to demonstrate esterase, most of the cells were stained. Many appeared to 

 manifest lesser degrees of activity than normal. This is significant in view 

 of the reported diminution or absence of this enzyme and other catabolic 

 enzymes said to be characteristic of malignant tumors in general. 1 The 

 acid phosphatase stain in histiocytic lymphoma showed enormous activity, 

 so strong that individual cells could not be distinguished. The activity 

 did not appear to be diminished. In a blood smear from a case of monocytic 

 leukemia, leukemic monocytes manifested esterase activity. In a similar 

 instance the monocytes showed strong acid phosphatase activity. Neutrophils 

 in the smear likewise contained much acid phosphatase. Study of sectioned 

 lymph node material showing typical Hodgkin's lymphoma revealed esterase 



