Immunological techniques to differentiate lymphoma from other malignancies

Seven patients, who had lymph nodes or masses examined by both immunoperoxidase staining and flow cytometry, are presented to illustrate the value of each technique including a critical analysis of the current application of these techniques in the pathology laboratory. All seven patients had diagnoses established by immunoperoxidase staining using antibodies directed against: Leukocyte Common Antigen (LCA), Epithelial Membrane Antigen (EMA), Neuron Specific Enolase (NSE), Leu M1, B4 or chromagrafin and synaptosin. Flow cytometry, which could be more rapidly performed, when sufficient cells could be separated from the node or mass, was diagnostic in two of the seven cases. Flow cytometry failed to show abnormalities in Hodgkin's disease or solid tumors, but it was useful in rapid diagnosis of lymphoma, provided that the sample contained mostly involved tissue. Nodes in which there was a minor infiltration with lymphoma cells could only be detected by immunoperoxidase technique.